Pontiac 5c heads YS stamp indicates the motor is from a 71-72 GTO or Firebird. One Pontiac 5C Head Pick up or can bring to the Pontiac Nationals in Norwalk or Trans Am Nationals in Dayton One Pontiac 5C head - Car Engines & Engine Parts - West Bloomfield Township, Michigan | Facebook Marketplace Gross valve lift was limited to just over . 442 lift, 112LSA)- this cam will improve low end response and work w/ Voodoo Hydraulic Flat Tappet Cam - Pontiac V8 262/268 - Lunati Power If you use the #16 heads, many think it is a good idea to have hardened valve seat inserts installed, for use with unleaded fuel. PDA. ,420/. Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! Pontiac 455 or 400, 5C heads. 428 . 1967 Pontiac V8 Head Bolt Set $55. All will need rebuilding 1 - 1965 326 - #62 2 - 1970 350/400 - #11 3 - 1975 all - #5C (8) $75 per pair Pontiac v8 heads - Car Engines & Engine Parts - Hopkinton, New Hampshire | Facebook Marketplace if you took that 061 head, and milled the other side of the chambers, you could make a very good facsimile of a hemi head. After the 6x heads, my next choice would be the 350 or 400 5c heads, followed by the mid '73-'74 #46 heads with screw-in studs. There are four stampings on the 5c's. 6 from a 1968 Pontiac Bonneville A 400 6. They are as follows; one cracked 670 head, 1 cracked 5C head, and EVERY 4X head I have seen[about 6] have been cracked in the center exhaust port. If need the actual compression of your setup now to complete this calculation. I used 2-Holley List 4224 660 CFM center-squirters on a OFFY 360* manifold, '67 GTO headers, a 1963 Muncie 4-speed, custom made drive shaft, Zoom clutch and pressure plate, Lakewood steel bell housing, battery went in the 5c head question Pontiac - Street. I tend to think they're 1. But, they both have press-in studs & small valves. Most, if not all '72 D-port heads had 3 digits, with a letter in the middle. hello all. Clean up and use, or rebuild them. 75:1 to 9:1). But they have 495 Pontiac Cylinder Head Upgrade & Engine Build - New Heads For An Old Indian - Engine Buildup. Compression Ratio and The Pontiac Engine. com) sells a 2111/416-inch Review (MPN # 5C-4 for sale) PONTIAC 93cc 2. Brand New. 00 (433 cid) or 4. 07-14-2004, 06:49 PM. Bill Biggest "sleeper" 1975 No. one is 1973 clean no crank or accessories $400 one is 1975, together currently w crank and pistons etc, $450 both standard bore 1974 j/k 6x-8 heads off the 75 400 above w rockers etc $140 1975 400 pontiac. 25 (460 cid) stroker crank and those same heads will produce 8. You have too much compression with 72cc heads and flat top pistons for running pump gas. 020 300 obo or trade Pontiac Heads - Car Engines & Engine Parts - Loogootee, Indiana | Facebook Marketplace Facebook 1974 400 190 HP YH A 8. Common Pontiac Numbers: Stroke: CID: 3. Customer: I own a 1971 Pontiac GTO Coupe 455 Cu in. The #11 or #18 heads can be used. 213 X 45 Deg. 66valve 101cc. pontiac 400 481988 blocks and 6x and 5c heads Rhode Island. 66 exhaust screw in stud 93cc same as 6x 4 heads. 04CC. The 6X-8 heads would give you about 3/4 to 1 point less compression on a 400 (about 8:1) than the #94 heads (about 8. O. 421 . the 061 head was the prototype in 1967. Here's a good head chart for reference Most all the normal Pontiac heads flowed about 195 - 200 cfm ( except the RAM AIR with round port exhaust), the 6x will come in around 210-215 cfm @ . Delivered fully machined and ready to 67-69 pontiac 428 head question. They are a better candidate for porting if you decide to do that later on. Screw-in studs are best because you don't have to have a Check the secondary identifier of the 6X heads to be sure of the chamber size- some were smaller (~93cc) others 400 6X were 101cc. the head code,on the heads is"5c". a 400 pontiac should make 400 hp without breaking a sweat. Categories. The RA IV has round port heads and the RA III has D port Heads. the Pontiac head 1968-up was a "spherized wedge". my question is head related The induction hardened seats started in '73 with the 4X heads at the earliest, but these heads were quite prone to cracking. The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Volume of 5C 1975 350 Heads: Pontiac - Street. Others say hardened seats are not necessary for normal street driving. Both heads have pretty comparable flow numbers, no clear winner in that sense. 3. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. These are the factory ratings, so the heads must be checked to be sure of the exact combustion chamber size. · Home Decor. 62 to 1 compression with the . Location is Pontiac Head Codes Home. but better cams are available now. my research says that they are 'smog' heads from 75 with only a 7. Head: Part II . The '75 5C heads are 101 cc, but they have smaller runners than the 6X. All will need rebuilding 1 - 1965 326 - #62 2 - 1970 350/400 - #11 3 - 1975 all - #5C (8) $75 per pair Pontiac v8 heads - Car Engines & Engine Parts - Hopkinton, New Hampshire | Facebook Marketplace I am building a pontiac 400. its been around awhile. 42 gear will be very noticeable, and if you ever get into a rebuild, a bit more compression, and an 068 style cam will help. com. As well as the E-Heads. Chuck_Neste Discussion starter. Roland Canted-Valve Pontiac Heads Plus A Scat Stroker Kit Give The Venerable Pontiac V-8 A New Remember Me? Join us now! Menu 5C-4: early '75 350 head 93-96cc 5C-8: early '75 400 head 100-101cc Smog galley cast & head machined for A. We have a great online selection at the lowest prices with Fast & Free shipping on many items! BP ports more Pontiac cylinder heads than anyone in the world. 2- 101 cc's. marchperf. Roland Racing CV-1 heads are machined with canted intake-valve seats and valve guides, which allow for the use of oversize intake valves without the worry of the valves being too close to the cylinder wall on standard 1965 Pontiac V8 Head Bolt Set sold. 040” quench (reused the . or Best You can also find yourself a pair of 6X-4, or 5C-4 heads and have them milled to get the chamber volume down to where you need it. Great condition. I have the intake and timing cover to go with it. Valve (Set) $84. 4:10 Pontiac Blocks- Bore & Stroke; Pontiac Heads; Pontiac Engine Torque Specs; Pontiac Cars (Body Types) Pontiac Engine Information; Instruction Sheets; 62, 13, 12, 48, AND 061 HEADS - MAY BE USED IN 4X, 6X, 96, 7K3, AND 5C HEADS FOR TALLER SPRING HEIGHT. 5C Pontiac Heads and intake 2 barrel intake and carb. it occurs inside Pontiac cylinder heads. 5 cr stamped O to right denotes HD springs: 1959: 389: 368-373HP: 540306: 1. 885" bore with a 3. M. 6 from a 1967 Pontiac Catanlina A 400 6. 77 exhaust valve, they flow better than any of the earlier big valve D-port heads did. An excellent head but Pontiac Cylinder Head Codes by Wallace Racing - Home of Pontiac Powered Firebirds,Trans Ams,Pontiac Powered Dragsters,Pontiac Power Rules! ===== 5C heads were installed on engines until around mid 1975 then dropped -5C-4- 1975 350 4bbl, 2. 4. 114 cc heads are for low compression 455 engines. specific Compression Ratio you are looking for. The engine has a 3. The 6X & 5C heads have factory hardened seats. 1969 GTO, 455ci, 230/236 Pontiac Dude's "Butcher Special" Comp hyd roller cam with Crower HIPPO solid roller lifters, Q-jet, Edelbrock P4B-QJ, Doug's headers, ported 6X-8 (97cc) The early 75 5C-4 & 5C-7 and the 75 or later 6X-4 were rated at 93cc. 5C-4's are just as good if looking for a Dport head that an be easily cut to 86cc chambers. These heads can be ported for optimum performance on a 450 HP street engine or a 700+ HP racing engine, and everything in between. bracket car. Most want the smaller chamber for the 400 for a good CR. Identical in performance to the much-touted '6X' casting head. Get the best deals for Pontiac 5C Heads at eBay. pumpgas 95,timing 12 -31° I did a build for a 67 'GTO back in 2010' and made the target HP your looking for. SD Performance has developed CNC porting programs for popular cast-iron Pontiac cylinder heads. Yup, that's the number of the heads - 143. These heads are comparable to the 6X which everybody uses on the 455 to give it a gas-friendly I have 3 pairs of pontiac v8 cylinder heads for sale. McKellar reasoned that Pontiac chose that particular amount because its cylinder heads generally contained rather large valves, and when combined with the small, high-velocity ports, high valve lift simply wasn’t required to attain strong performance. Head codes - 51,5C,6X,6S,6H; 2-101cc's: probably special 455 head for 455HO T/A: 4-91 cc's: [Archive] 4X vs. View Full Version : 4X vs. Exhaust Crossover Port Matchings INTAKE MANIFOLD BOLT PATTERN IS THE SAME FOR ALL 65 Get the best deals for Pontiac 5C Cylinder Heads at eBay. 300 intakes, & 1. 500" lift. 499 posts · Joined 2013 Add to quote; Only show this user #1 Pontiac heads specifics I guess they would make a great super charged head with such a low 8. PY Online Forums - Bringing the Pontiac Hobby Together > General Classic PONTIAC TECH > Pontiac - Street > why are 5C head castings so ugly? Reply Thread Tools: Display Modes #1 08-23-2019, 08:04 PM F ROCK. 450-. (because edelbrock or Kaufman aluminum heads might be too expensive). New P255/60 R15 Cooper Cobra tires. 00 . Free UPS Shipping. holley 850. So, that makes the 6X heads the best iron head value, for a Pontiac engine build nowadays. Funny how the Ram Air V gets the worst exhaust-to-intake port when it was capable of propelling a '69 GTO down Ultimate Pontiac Head Flows. The 5C heads are some of the better flowing Pontiac heads, and it is a 350 so there is some hope. My plugs are r45ts. Location: sicklerville nj 08081 Bare 356-T6 Aluminum, 400+ cfm flow out of box, 50cc combustion chamber, 310cc intake port, Will accept up to 2. 77) on 5c's. stock suspension street GTO's to heads that run 8. 5C (1975 350/400/455-cid D-port) Date cast: F184 Grade: 1 Valve sizes: 2. Ferrea Hi Perf. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass. 60: 69 cc SD head: 1959: Here is where you CAN use the aftermarket aluminum heads, but figure on about $2,400 for a set of PONTIAC heads, un-modifed out of the box. The multiple layers allow for varying degrees of thermal expansion while providing maximum sealing capability in applications where extreme cylinder pressure exists. Bigger is better, in this case. With porting, they can flow very nice numbers. I would suggest upgrading the #94 heads to 2. Beginning in 1968, Pontiac fitted their highest-performing engines with heads featuring redesigned round exhaust ports (shown above). Dave has put in a lot of hours in the last month, inputting data from his own hand ported heads. 5C heads for a 455 Pontiac - Street. 11/1. Returns; Ordering & Delivery; Payments & Financing; International Shipping; Request Price Match; Contact Us; Builders Still hung up on Pontiac engines, i decided to replace the stovebolt six and install a stock 1970 455 Pontiac engine in the '55 Chevy. Stock valve train with Isky polylocks. 67 out of 5 stars When it comes to cast-iron Pontiac cylinder heads, the Round-Ports are the fancy of every performance enthusiast, but the smog-era D-port (4X, 5C, and 6X) castings have proven a performance bargain. hooker super comps and 3 inch bullet mufflers. The May 7, 1973 changeover date is Motor Unit Number 709986 assembled on or about May 7, 1973 May 7, 1973 is the head assembly date, NOT the casting date. 2. Pontiac Cylinder Head Search There is also a picture to show where to find the secondary stamp. 5 Welcome to Forever Pontiac, where we keep the memory of Pontiac alive with great discussion, maintenance tips, Description Stock 400 and TH 350 trans and open 2:56 rear end. In my 20 years of engine machining I have seen several cracked Pontiac heads. A 351/48-inch-od deep-groove pulley is still available from your GM dealer under PN 3829387. 6 H. Opens in a new window or tab. We have ported D-Port heads that run low tens in 3,700 lbs. 5 with steel 64 heads the heads that were made by Kauffman are 72cc cnc d port took 55. 92/1. Factory A/C upgraded to R134a. Save Share 15 Pontiac heads. There are a lot of sites with Pontiac info. Shop Edelbrock E-Street Cylinder Head For 1975 Pontiac Grand LeMans 04A3ED-2B5C. If the shape is different I will need to figure out how much to mill. Find out what the heads are on the 455 and we'll go from there. 7 from a 1968 Firebird The owner rebuilt it in late 2011 and swapped the 5C heads for the 6X heads. Afton, OK. I think that the 6X-8 would be the best for your engine, using pump gas. [block#481988]. 5C Pontiac - Street PY Online Forums 4X vs. FAQ: Members List: Social Groups Most, including many pro engine builders, agree that 9. Since Pontiac offered the 400 2-barrel, the 400 4-barrel with both manual and automatic transmissions, and the 455 4 Wallace Racing Pontiac Cylinder Head Milling Chart Pontiac POWER Rules! BACK Contrarily, the number-4X, -5C, and -6X castings make excellent, affordable choices for high-performance rebuilds. The way Pontiac changed compression ratios throughout the years was by changing combustion chamber size. 11" valve from the factory. (3. The 5C-8 head is pretty much the equal of a 6X-8 heads. $1,487. Pontiac Head ID Cylinder Head, Performer RPM, Aluminum, Assembled, 72cc Chamber, 215cc Intake Runner, Pontiac, 389-455, Each. Pontiac 1973-1974 Cylinder Heads; No "H" stamp on early 1973 heads. 30 over, new sealed power bearings, Thinking about just using my ~100cc 5c-8 heads which are fully rebuilt and look very decent. I am meeting with him this afternoon to hear it run and help him pull it if I decide to buy it YES ! Swap the heads. Part Number: EDL-60599 4. Pontiac 428/455 stock ,5C heads 2,11-1,66,Castiron intake ,komp 9. 301 . 00. Ultimate Warrior : Join Date: Jun 2003. 6 rocker arms on my 500/510 hydro roller cam make little more power just does not feel fast . 466” lift of that cam is fine, but it’s pushing the exh valve springs to there limits. March Performance (Westland, MI; 734/729-9079 or 888/729-9070; www. Remember Me? Join us now! Menu. Custom Interior completely redone . Pontiac 5C heads pulled from an early ‘75 Trans Am. . Which version of 6X do you have? 5C's are similar to 6X-8's cc wise. Categories No, you don't want 455 heads. If you scroll down to Head Search, there are several heads listed and the combustion chamber sizes given. Refinished Rally II wheels . 0 255 4X 1-2 7044066 Block Casting # 481988 According to Wallace Racing and another source, 5c heads were used in '75. They are as good as any D-port head really, just they have a big tendency to be cracked. Will Tin Indian Performance's 400 Block and Kauffman Racing Equipment's Head Combo Produce More Than 600 HP On 93-Octane? - High Performance Pontiac Magazine. 11" intakes/1. 5 hp vacuum cleaner motors), two graduated vertical manometers to measure atmospheric pressure, an incline manometer to measure actual airflow, and a velocity probe. 030" over 400, flat top forged not cast, modern rods, stock 670 heads, custom hyd cam close to RAIII specs. Reworked Q Jet, a cast iron EGR intake manifold, along with a set of headers. The heads are 5C's from '75 that flow roughly 200cfm intake at . I pulled these at least ten years ago from a running 400 but I would have them rebuilt so consider them good cores! I don’t see any cracks visually but feel free to inspect them. On the RA IV the exhaust ports are all 4 round as opposed to the standard vintage Pontiac where the end two ports are ovoid and the center two are D shaped. 66 valves, chambers 92 to 94ccs usually) are exactly the same as the 1975-1/2 thru 1977 6X-4 350 heads that are so popular. Pontiac heads dont support high RPMs well either, The 5C-8 is probably the worst head you could be considering, with it's huge 114cc chamber volume you will need a big dome on your 389 piston just to get to 9:1 compression. 5C-8, 6X-4, 6X-8, and 6H-6 castings. 110 x 5. 5C are about 7cc smaller and the 4X are about 5cc smaller. Location. Cleaning + magnafluxing your cores $130 per pair; Fill exhaust crossovers with aluminum add $100. You can have the heads opened up to accept 1. We also specialize in porting RAII, RAIV, H. 400-inches for most applications. Fat Ivan Pontiac 5C Heads. "The 6X and 5C heads have one advantage over all the other choices, that being a superior intake port shape with a better short-turn radius. Heads will be going on top of a 455. $100 obo for all! Pontiac 5c heads and 2 barrel intake - Car Engines & Engine Parts - Itasca, Texas | Facebook Marketplace Roland Racing offers aftermarket canted-valve Pontiac head castings as both bare heads and assemblies for pre-1980 Pontiac V-8 engines. Remember Me? Join us now! FER-F5074-8: 2. I would suggest that you try to find a pair of later heads with a little larger combustion chamber like 46 from a '73 or '74 350, or 5C-4 or 5C-7 from an early '75 350, or 6X-4 used on some 350s after late February 1975. This is a driver quality car ready for got some 17 heads to replace the 5c/8's so i could raise compression on my 400 build. airforrest Just wanted to let everyone know that SD Performance has got their CNC program for 6X and 5c Iron D ports done now. I am in the middle of figuring out a new build for a 1975 Pontiac Firebird with a 350 PONTIAC engine. 9770716) Basically, all Pontiac D-port heads with the 2. We have a great online INTAKE MANIFOLD BOLT PATTERN IS THE SAME FOR ALL 65-79 HEADS. Up into the early 90's, most traditional Pontiac guys scoffed at the 6X heads, & didn't know about the secondary (stamped) codes. (IMO) There is a secondary code on them that needs to be found. LOOOONG list of new parts and recent maintenance. I. True dual exhaust with chrome T/A tips. As said above, a 3. SPEED SAFE, AIR RAM Free-$150 a pair 5c-4 or 6X-4's milled . 66" valves, 4. There may be a mild cam installed as the engine seems to have more power than stock. 060 (add $100-125) then resulting 81-84 cc, big intake valve, screw-in studs. The 6X heads weren't produced until 1976, 4X were 73/74 heads. 50:1 SCR, Hello folks. Pair #5C (8) Heads $425. Now the car is really nice and clean and I DO NOT want to change the engine out to a 400. 50's in a 2,400 lbs. There were no 72 cc 46 heads in 73-74. 5:1, depending, of course, on bore size, What About 5C Heads Pontiac - Street. Those old Pontiac heads are I know the 2. 949" valve length, 30/45 degree seats, threaded studs, 93cc It seems that Pontiac cylinder heads cast between 1967 and 1972 are typically the most sought after for restorations or performance. 5C heads plugged with smog devices removed. 5 with alum heads. 11" intakes will clear because the 1975 5C heads already have a 2. 77's though. flw file Most mild street applications will experience an easy 50+hp gain over stock heads and even more with more aggressive combo's!!! Additonal Options for above heads. 060/. 5C Most undercammed 1963 SD, 1971 455 HO, 1973-74 455 SD (tie) Most underexhausted 1964 GTO (No. Moderator: Team. General engine tech -- Drag Racing to Circle Track. When opened up to the 1. Only selling to make room for other engines. FAQ: Members List With stock 6X heads or 5C heads you have about . $150 $200. 6CR. 7- 98cc's. They made about 7. 66 valves. Condition: New. The key to maximizing the performance of any combination is proper component selection. I'd run a GOOD 800cfm Q-jet. Blowby can be caused by the heads if the guides are bad enough, depends on how bad it is. Will need gone through. The 6X is the better of them though. 66 6x-4 Trans 6x compatible with PONTIAC FIREBIRD GTO 400 455 350 1975. Your account. Pontiac knew how vital cylinder heads are, even back in the 1960s – that’s why its engineers devel-oped so many amazing heads, like the ’68 Ram Air II “96” heads; the “722” and “614” Ram Air IV heads of 1969-70; the “197” or “7F6” HO heads of 1971-72; the “16” SD heads of 1973-74; or, of course, the i had an RPM intake on my 455 powered 69 custom s over 15 years ago. After 1967 the heads were open chamber heads. I think, with the #62 heads and subsequent increase to 9. This Calculator is designed to tell you how much you need to mill your heads to achieve the . Date codes on heads j034 i064 no other modifications have been made to the heads pontiac 5c 4 heads I was saving these for a future project, but my plans have changed. You won't need the hardened exhaust seats on the 455 heads and depending on the amount of miles he puts on the car he won't need them in the 143's either. They are usually stamped on the machined pads by the valve covers. Dearing, Kansas · Within 621 mi. 5 is the highest SAFE CR, with iron heads, and 10. 5C. Pontiac used the Someone has installed a 1975 400 with the 5c heads. 66 or 1. stock suspension street GTO's to heads The 6X-4 head is a very good head. 750" stroke. Hi Performance Pontiac did a test years ago, and for the street, big 2. Complete, magnafluxed & ready to I have 3 pairs of pontiac v8 cylinder heads for sale. 6 compression ratio. Gives 'em a headstart over 205cfm 6X's. I've got a set of 5C's from my '75 400, or I could pick up a set of 4X's from an older 400 (at the local boneyard). SEARCH: Tripod The Web: Pontiac made closed chambered heads until 1967. After years of extensive R&D both on the flow bench and on our track, we have developed some of the best performing round port and D-port. Search for Pontiac Cylinder Heads As You Go Thru Life DO A WHEELIE !!! You Searched For: 165 Matches Found (displaying 1 to 25) Year: Engine: Hp: Code: Valve: Misc: 1955: 287: 173-180-200 stamped X to left of center head bolt - 10. Price: $117. I have since pulled the #15 heads for #197 455 HO heads, aluminum intake w/ Q-jet, and factory HO exhaust manifolds on the same short block with the 2802 cam. , and 1973-74 Super Duty 455. The TH350 automatic transmission has a shift kit installed. Browse all. Just curious about what y'all think about 4X & 5C heads. See all. 66" exhaust to 1. Every bit as good on a 400 as the 1971 #96 400 heads (96ccs + chambers), Get the best deals for Pontiac 5C Cylinder Heads at eBay. Jump to Latest 901 views 4 replies 3 participants last post by BrianB74SD Oct 10, 2021. This should free up a lot of turn around time on head porting. We were armed with a 400-cfm laminar flow element (powered by six 1. The best hardened exhaust seats started in '75 beginning with the 5C heads. MLS gaskets are the ultimate in cylinder sealing. Remember Me? Join us now! Menu The cool thing about a 400 w/ 6x heads is that you could run it with the stock 3. Ultimate. PONTIAC POWER RULES ! ! ! BACK. Free Pontiac Heads! Jump to Latest 1K views 6 replies 3 participants last post by nitro_baller4692 Sep 21, 2006. 2800 rpm ATI converter. The 1975 5C-4 350 heads (2. 800 exhaust valves, Guides & seats included The. Heads with casting dates starting around mid-March 1973 to mid-April 1973usually will have screw-in studs. 326 . D. Pairs have ID numbers of 5C, 6S, and 4X Make offer for what you need Marketplace. Engines so equipped were the ‘68 Ram Air II 400, 1969-70 Ram Air IV 400, 1971-72 455 H. e. 9- 91cc's. Then to really take advantage of the extra flow 5C-4's, 5C-9's, or '70 model On the 5C to 6X head, 400's & 350's transitioned from their respective chamber size 5C's to 6X's in Feb of 1975. 11 Heads 1. 2 40x40 black outs Price is for one. Pairs have ID numbers of 5C, 6S, and 4X Make offer for what you need. We have a great online selection at the lowest prices with Fast & Free shipping on many items! I think most of those heads without the end holes were D-ports from the 1972 model year. off face of heads to bring compression back up block also 0 deck Kauffman ported to 310 also used 1. In light of this, the 'Year' entry, as indicated by the chart below, may actually represent the year that the heads were cast, versus the year that they were actually installed on an automobile. 030 overbore, #5C heads, mild cam, It bears the engine block code YK and the casting number 481988. 5C heads are almost identical. For sure some ignition timing improvements and some Q Jet tuning will help. Ive been chasing what im thinking is some type of spark knock. 95: Ferrea Ultimate Race Valves The 6000 series competition valves are designed to provide excellent reliability in an environment of high sprng pressures and roller cams, at a budget price. By expanding on the approach that Pontiac took when assembling combinations for its production vehicles, selecting This is mainly due to the minimum valve bowl diameter in the SBC head being a tad bigger then the Pontiac The 670 heads have the lowest port I ported the 5C heads at the time, along with a fresh valve job. Different chamber volumes, some huge for 455 engines and some small for 350 cid. 46's on and parked the stock 5C heads, since the no. 400 . and S. 11 intakes and smaller 1. 025 pulled of running engine. _____ '73 Formula Many companies produced stock-replacement Pontiac head gaskets over the years, but few were as good those originally supplied by Pontiac. 75 . Would the r45tsx spark plug make a difference. my 68 firebird has a 68 full-size 400 motor and th400 trans with 5C heads on Pontiac made closed chambered heads until 1967. this number is XXXXX the center of both of these exaust ports on the heads. funny it gets 17 hg of vac could that be hurting my I have a rebuilt Pontiac 400 with 5c heads. i had stock 6x heads as well but on a 455. 23:1) axle and the complete M-20 4-Speed changeover, all of which is going in behind the 60,000 mile Pontiac 350. BUT, other things can affect this safe number. We have a great online selection at the lowest prices with Fast & Free shipping on many items! Skip to main content. And this is with good quality 93 octane gas. 66 exhaust worked well. Most of us are going to upsize the 1. Int. 8:1,edelbrock 650 Avs. 400 automatic with 5C heads. 1974 46 heads milled. Greenville, SC. ok so i have a pontiac 428 im rebuilding it was an engine my father built about 30 yrs ago. Think of it this way, if 5C's were stock 220-230 cfm (@ . Both are great Pontiac heads but they are quite different. 030” Cometics). 8 posts • Page 1 of 1. Would trade for a good 4-bolt 350 core. ALL heads need to be measured for chamber size regardless of what they are "supposed" to be. 11"/1. In our last issue, we began our foray into the world of airflow, as. Welcome Guest My Account Order Status Wishlist (866)762-7527. Stock Pontiac Head Flow Head Casting Number: Year: Notes: Porting: Intake Lift: Intake Flow: Exhaust Lift: Exhaust Flow: Download Desktop Dyno 2000 . 6- 101cc's. Below are some popular heads and chamber sizes (always be sure to have yours checked before any milling). Heads off a 455. Pontiac Blocks- Bore & Stroke; Pontiac Heads; Pontiac Engine Torque Specs; Pontiac Cars (Body Types) Pontiac Engine Information; Instruction Sheets; Compression Calculator; Ask a Tech Question; Customer Service. 1975 High Performance 100. The 16's are a good choice, 5C HEADS 74-76 Firebird & TA TECH. Create new listing. 5c heads. Hey, I am restoring a 1970 Pontiac lemans and I have a fully restored 400 block bored . 7/16 Rocker Arm Stud and Lock Nut Upgrade Kit for 1967 and later heads (Set/16) Welcome Guest My Account Order Status Wishlist (866)762-7527. Here are some ways of finding out and changing your compression ratio on Pontiac V8 engines. Air & Fuel Delivery; Apparel, Cups, Decals Pontiac Heads; Pontiac Engine Torque Specs; Pontiac Cars (Body Types) Pontiac Engine Information; Instruction Sheets; Compression Calculator; Ask a Hi Bear motor was 9 . High Performance Pontiac Mag June 05, another fine article by Rocky Rotella on the 70's cylinder heads. Products. I removed the intake manifold off the car to repaint it, when placing the intake gaskets they fit perfectly onto the heads however, I noticed the small center ports on each head has a smaller rectangular port just above them, the gasket does not cover the rectangular port and it is left opened. They also have pressed in studs and are around 72-75 cc. Marketplace access. A. Intake Hi Performance Pontiac did a test years ago, and for the street, big 2. But since your date code is June 12 1974, that seems a little early to be Cylinder Heads. Also if it sits In 1975 Pontiac started stamping extra numbers (1/4" tall) on their heads. Pontiac 5C Heads. 061). Have a couple of 481988 two bolt undrilled blocks. Removed from a 389 with #77 heads. Stampings on Head codes - 51,5C,6X,6S,6H : 2- 101cc's probably special 455 head for 455HO T/A 4- Does anybody know if the 4x and 6x head have the two outer holes drilled and tapped for the exhaust manifolds? I know some of the early 400s did not and only used 4 bolts on each manifold. The 5c heads preceded the 6x heads somewhere around '74-'75. I think the main purpose would be the air flow comparison between the different heads. The readings may be 10% high. Pontiac redesigned the head by raising the intake ports so the short turn into the bowl is at a better angle. $12 $15. 77" so the hardening will be gone anyway. The casting numbers are on the outside of the head. dur. MUST USE A LONGER PUSHROD) Item #: FER-F5144-8. Vehicles 1970 Pontiac 455 cylinder head question. My 5c heads are in fact drilled but am thinking of buying a reman engine and they said they run either 4x or 6x heads. In 1967 Pontiac made some open chamber heads(i. 960/4. FAQ: Members List: Social Groups: Calendar Pontiac 5C Cylinder heads: $250 Came off of a running 1974-75 casting 400. meaning a wedge head with half a hemi chamber milled into the spark plug side. 540” retainer to guide clearance so the . 75 stroke crank on 87 octane, and then rebuild it later w/ a 4. now to your motor. 00 per pair ; Hardened exhaust seats machined and installed add $120. The HO heads have 108 cc chambers and calculates out to 8. I have taken the motor and trans out and was wondering how I could improve the horsepower? Pontiac made all their horsepower with the heads. 1975 No. pump gas engine. round port heads. The "5C" part will be a cast lettering, 1975 5c heads milled . R. mothermuxer. But if you intend to keep the stock heads, I'd suggest a summit K2800 (262/272 adv. These head numbers represented chamber sizes. 500 lift @ 28") heads, every Pontiac headporter/engine builder in the country would be using them for basic D-port pump gas 455 builds. The seller is asking for $3,000. 6x-4's, 5C-4's, 5C-7's, all 94-96 cc as cores: It does not take a lot to get a Pontiac head to flow well enough for a good street build and it saves you money over the aluminum heads. Some is correct. Considering the investment, the engine was a Terry McGean:The 124cc heads we used on our '76 455 for the story you referenced were indeed worthless, having the hugest chambers of any Pontiac V-8 heads, but our sources show that your 5C heads A 400 6. 6 CR. my 68 firebird has a 68 full-size 400 motor and th400 trans with 5C heads on them. In the late '70's, they put 6x-8 heads on 400's. The 4X head was the 49-state casting used on all '73-74 400 and 455ci engines. 21 Pontiac 5C heads pulled from an early ‘75 Trans Am. The late '73-'74 #46 heads can be used. 46's offered better compression and had been reworked w/ bigger 2. Jump to Latest 5K views 2 replies 3 participants last post by JohnnyB Oct 15, 2014. my_67_camaro New Member 2021 2:24 am. I've seen conflicting info on some charts regarding the size of the exhaust valves (1. Large intake valves, screw in rocker arm studs, and larger 98cc combustion chambers that work great to bump up the compression ratio of a 455 or 462 stroker. 94. the comp 525 305 cam. there are two more #s ,one on each By chatting and providing i goolged pontiac head codes & the chart said that "5c"was a 1975-400-185hp. I have not taken the 5C heads off yet but I am assuming that the chamber shape is the same just larger. 66. Location: sicklerville nj The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Complete with valves and rockers, etc. 350 . There is more in a thread HERE, as well as other info on this forum- hit up the search for 'Pontiac 400', etc. 1975 400 pontiac. pump feed line: 5C-7: believed to be 400 5C-9: believed to be 350 head The exhaust crossover problem can be solved by filling crossover in head with aluminum or using the stainless steal shim trick to block the dummy hole. they cc'd at 88! The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Also, some say they need hardened valve seat inserts, for use with unleaded gas. 00 per pair I have these 72cc heads that I would like to use and the heads on the engine right now are 101cc so I could have him mill half the distance between the two. About Us. mojonelo Remember Me? Join us now! Menu I recently rebuilt a 75 350P for Derrick- we swapped a set of no. O from a 1976 Trans Am A 350 5. It was for 350's so the chamber is usually in the 91-93 cc range. Pontiac 400 with the desirable 481988 block that can be built to handle high HP. Vintage Pontiac heads 3 pairs of heads. 77" valves during the head rebuild along with the BB Chevy screw-in studs you mentioned. The 350, 400 and 455's all had different heads. The 5C & 6X's are near identical heads & when I had my 6X-400 longblock core deal going ran across a '75 400 with one of each casting style, very close dated, & pulled of original engine with GM head gaskets. It should put the CR somewhere between 9:1 and 9. 8- 98cc's. 5c head stamped 4, Get the best deals for Pontiac 5C Head at eBay. On a Pontiac engine the compression ratio's were change by using different heads. 77 exhaust flow pretty close the same. In 1967 Pontiac made some open chamber heads(i. Stock Pontiac Head Specs * During my searching for information, I found quite a few discrepancies in the sources I was viewing. The 1974 Pontiac 400 engine on offer has been rebuilt with a . 4- 91cc's. Disclaimer: Take these air flow readings with a grain of salt. The very 1st thing that comes to mind is the fact that the 72cc Hi comp 400 heads from '68-'70 will work real good on a 350 block. I believe the number for the '72 400's was 7K3. 4X, 5C, and 6Xs are shown. hhx cysqxcjk gofnf vahh jbbqimp lghvkiz etlb rfnzjn ohf aoazq