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Bernie Froman
Tribal Scout

2 Posts

Posted - 24 Jul 2007 :  09:22:21 AM  Show Profile  Reply with Quote
The engine that I am planning to install in my 40 Pontiac has heads that do not have both bolts holes at the fwd and aft exhaust ports. I want to install headers with a good seal. What other heads[w/6 bolt holes]at the exhaust ports will work? There are a myriad of numbers on the head and block castings. Which ones are relevent?

I'm new to this website and have zero Pontiac engine history.

B.Ray

mike389
Big Trees

USA
568 Posts

Posted - 24 Jul 2007 :  12:20:14 PM  Show Profile  Reply with Quote
bernie
i had a little problem with 7L4's with the stock logs having 4 hole's when i switched to #15 heads with 6 hole's, but the 4 hole manifolds bolted up using copper gaskets with no leaks using 4 bolts, headers are evidently a different scenario with the flanges being thinner! on page two check post june 26 george having same problems. with engine out of car is the time to fix this problem, brackets probably work ok but drill and tapping the hole is the best way to go! check george's post!
good luck
mike
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hugh
Cochise

USA
430 Posts

Posted - 24 Jul 2007 :  12:54:48 PM  Show Profile  Reply with Quote
Bernie - sounds like you have a set of # 7K3 heads, used in 1972 on the 400 engine. These heads are in fact missing the two end bolt holes and are prone to exhaust leaks. Otherwise, these are good heads. Most all of the other Pontiac heads (not familar with the 7L4) will have the 6 bolt holes. But there are different chamber sizes (cc's) and valve sizes. Late 60's and 70's Pontiac heads have their id # cast on the center exhaust port.

If you can give us more info on the engine, one of us will be happy to recommend a head # that would work on your engine. The engine code # is stamped on the front of the block between the water pump and the head on the passenger side. Examples: WC,YC,ZX,YS......

Also, the later Pontiac engines have the engine size cast into the block on the driver front of the block and on the passenger side in the middle of the block, usually this one can't be easily seen because it is behind the dip-stick tube.

Hugh
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Mr. P-Body
Running Bear

USA
2258 Posts

Posted - 24 Jul 2007 :  1:15:06 PM  Show Profile  Visit Mr. P-Body's Homepage  Reply with Quote
Bernie,

Since you're new to Pontiacs, I would highly recommend you buy Jim Hand's "How to Build Max-performance Pontiac V8s" by SA Designs. This is the most current study of the ol' Injun, and has a wealth of information about the facts and myths behind GM's first and most sophisticated race engine. You can get the book from most regular book outlets and websites catering to Pontiac guys and gals.

Jim
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mike389
Big Trees

USA
568 Posts

Posted - 24 Jul 2007 :  1:15:57 PM  Show Profile  Reply with Quote
hugh
the 7L4's are identical except for CC's i had a set of 7K3's and could find no difference between them! the 7L4's were used on '72 455 engine, far as being prone to exhaust leaks i had no problems at all using copper gaskets!
mike
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DiamondJim
Cochise

328 Posts

Posted - 24 Jul 2007 :  1:18:31 PM  Show Profile  Reply with Quote
These might help: http://www.spottsperformance.com/headLbracket
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Cobrabill
Talking Dog

Aruba
3128 Posts

Posted - 24 Jul 2007 :  6:33:11 PM  Show Profile  Reply with Quote
Last i knew the 72 455s came with 7M5s.You might want to CC them.

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mike389
Big Trees

USA
568 Posts

Posted - 24 Jul 2007 :  8:44:21 PM  Show Profile  Reply with Quote
cobrabill
not to get off the beaten path on this thread but the '72 455 had five different numbered heads including the HO 7F6 rd. port!!! 111cc the others are 114cc
mike
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Mark S.
Cochise

USA
432 Posts

Posted - 24 Jul 2007 :  8:50:19 PM  Show Profile  Reply with Quote
Bernie - Go to page 2, look for a thread titled "7K3 Heads", authored by george. Good info there.

Good Luck -

Mark

PSP Member since 1996

Never enough cubes...

"The difference between genius and stupidity is that genius has its limits." - Albert Einstein

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Cobrabill
Talking Dog

Aruba
3128 Posts

Posted - 24 Jul 2007 :  8:52:20 PM  Show Profile  Reply with Quote
I'm aware of the H.O. numbers.Bernie doesn't say what motor.114 CC heads on a 400 is going to give around a 7.1 CR

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mike389
Big Trees

USA
568 Posts

Posted - 24 Jul 2007 :  9:33:28 PM  Show Profile  Reply with Quote
the 400 had 7H1 small valves,and 7K3 big valves for the 1972 engine @ 96cc's 8.4cr. hopefully he has one of this two and not the bigger chambered heads, waiting for his info!!! i had the 7L4's on my 389 and even milled down 60 it don't come close performance wise to the #15's @ 84cc's
mike
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Will
Cochise

Zimbabwe
285 Posts

Posted - 25 Jul 2007 :  02:04:07 AM  Show Profile  Reply with Quote
Bernie,

Welcome to the world of Pontiacs. The picture below shows you the relevant location for the numbers you need to identify a Pontiac head. Most Pontiac heads do NOT have the secondary stamping as shown in this picture, that's a feature of some of the '70s heads. Also, the date code might be in a different location on earlier heads. The casting number, which is the really important number most of the time was always right on the roof of the center exhaust ports as pictured.

Many of the small valve heads also did not have the end bolt holes drilled from the factory. The flanges and material is there unlike the '72 castings but they just weren't drilled.

Let us know what casting number your heads are and we can help you with more information about them.



Not qualified to answer questions about engines over 425 HP.
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Bernie Froman
Tribal Scout

2 Posts

Posted - 25 Jul 2007 :  09:34:27 AM  Show Profile  Reply with Quote
I'm overwhelmed with your response. I appreciate the help.

Here are some numbers I found:
Block---F104-74, DN2, 481988, 400 GM-7-DM, 512657YF, 24P271112
Heads---7H1 on both, B152 [passenger], B012 [driver]

B.Ray
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Bill Boyle
Horse Feathers (Charter Member)

USA
4797 Posts

Posted - 25 Jul 2007 :  10:32:50 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Welcome to Pontiac Street Performance.

The heads--7H1 on both, B152 [passenger], B012 [driver]

The letter B=the month of casting, B=February; the number 15 is the day, and 2 is the year (1972).

7H1 is the casting ID and from experience is from 1972. Others have provided info on these heads. He's some good info for future reference.
http://www.pontiacstreetperformance.com/psp/heads.html

Mr P-body's suggestion to buy Jim Hand's book is a good one and the book will be quite helpful to you. There are many other good sources as well that provide info that will be helpful too. I suggest subscribing to High Performance Pontiac (HPP). There's plenty to glean from that magazine. I have them going back to 1982. It was helpful to me and kept my interst in Pontiacs thriving. You'll look forward to each new copy and you're sure to pick up information that is good. Once you realize you know something you'll then realize how much you don't know. You'll also begin to form opinions and see that what the mags state is not always 100% accurate.

I read Jim Hand's book often and I've been in this hobby for 40 years. I learn something everyday. That's what makes it all interesting. Many of the guys that reply on this board where were you are right now 3 years ago. Through study and doing, there experience and knowledge base have grown. This web site an others like it have bolstered the Pontiac spirit. Again, welcome to PSP and enjoy your Pontiac.

Bill Boyle

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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hugh
Cochise

USA
430 Posts

Posted - 25 Jul 2007 :  1:06:04 PM  Show Profile  Reply with Quote
The 7L4 head was used only on the 455 in 1972.
The 7H1 head was used only on the 350 in 1972.
481988 block cast # was used on the 1970-74 400 engine.
The "YF" code was used 1973-74 for the 400 w/auto.
F104 means the block was cast on June 10, 1974.

Summary - you have a 1974 400 engine with 1972 400 heads.

Bernie - you most definitely need a better set of heads. I suggest a set of 5C-4 or 6X-4 heads. The are common/easy to find, are inexpensive, and flow well. These have around 91cc's and will give you around 8:1 compression. Yes, you can cut these, mill the block and so on, get them up to 9:1 if you want and there are many other heads (96,6S,4X) that would work well also. Look for heads with screw-in studs.

Edited by - hugh on 25 Jul 2007 9:43:10 PM
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mike389
Big Trees

USA
568 Posts

Posted - 25 Jul 2007 :  2:05:51 PM  Show Profile  Reply with Quote
hugh
the info on the 1972 7H1 heads on this site and wallaceracing.com indicate that they are 350 heads 1.94/1.66 valves 7.6cr./80cc's 175 HP, were did you find the info for the 455? the only heads i can find on the 455 is 7L4,7L5,7M4,7M5, and 7F6 rd. port!!
mike
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Brian Baker
Mongo

USA
1050 Posts

Posted - 25 Jul 2007 :  2:09:34 PM  Show Profile  Reply with Quote
I think Paul Spotts has a pair of these "7H" series heads on his blown alky dragster. They're essentially low compression 2-barrel carb station wagon heads.

Will Rogers never met a liberal.
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Brian Baker
Mongo

USA
1050 Posts

Posted - 25 Jul 2007 :  2:15:47 PM  Show Profile  Reply with Quote
Yup...check here:

http://www.spottsperformance.com/Dragster%20images/newdrag17.jpg

http://www.spottsperformance.com/dragster

http://www.spottsperformance.com/Dragster%20images/newdrag14.jpg

I've talked with Paul in the past about his 428 combo, and his compression is low enough that he could get away with using race gas (something to the tune of 8:1), but he chooses to run alky anyway. If he were to bump the compression to 11:1 or higher, this car would be in the sixes. Sorry but these heads on your 400 will produce an abysmal CR.

Will Rogers never met a liberal.
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mike389
Big Trees

USA
568 Posts

Posted - 25 Jul 2007 :  2:36:57 PM  Show Profile  Reply with Quote
brian
i entered the numbers in the C/R calculator on this site using felpro specs and -6.7 for valve reliefs and 80cc's indicated on the chart, don't know if that is correct on the valve relief spec, but C/R came up @ 9.2:1, used wallace chart which is a little different with close results. maybe the numbers i plug in are not right!! how low a compression ratio do you consider abysmal say for street use?
mike
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Brian Baker
Mongo

USA
1050 Posts

Posted - 25 Jul 2007 :  2:43:00 PM  Show Profile  Reply with Quote
Anything below 8.5:1 is abysmal...unless running boost. Do you even know what Bernie's heads CC at? Or are you just going by the CC that is printed on the wallace site (which could be incorrect)? If the chambers in Bernie's heads are the same size as the heads on Spotty's dragster (and my hunch is they very likely are), his compression is about 7:1. Besides, there are far better heads out there with larger valves, that will provide a decent 9:1 CR, that are inexpensive for Bernie's combination. Paul Spotts has the luxury of being an engine builder and having "cheap" and quick access to a machinist to make these junk heads work for him...of course a 6-71 blower turning about 30% over doesn't hurt either.

Will Rogers never met a liberal.
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mike389
Big Trees

USA
568 Posts

Posted - 25 Jul 2007 :  2:54:21 PM  Show Profile  Reply with Quote
brian
thanks for the info, bernie's CC's are not known so unless CCed all we have to go on is these charts which this site readings are the same as wallace's
thanks
mike
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Cobrabill
Talking Dog

Aruba
3128 Posts

Posted - 25 Jul 2007 :  3:00:42 PM  Show Profile  Reply with Quote
7.1CR?Hmmmm,where did i hear that number before?

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mike389
Big Trees

USA
568 Posts

Posted - 25 Jul 2007 :  3:44:11 PM  Show Profile  Reply with Quote
bill
unless the charts are wrong the 7H1 heads only came on the 350 c/i not the 400, these heads evidently were installed later on the 400, the only way it could end up @ 7.1 is if they opened up the chambers or the 7.6c/r is indicating that the CC's is much larger than 80cc's listed from the factory which indicates more than one 7H1 chamber size was available!
mike
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Brian Baker
Mongo

USA
1050 Posts

Posted - 25 Jul 2007 :  7:45:40 PM  Show Profile  Reply with Quote
quote:
Originally posted by mike389

brian
thanks for the info, bernie's CC's are not known so unless CCed all we have to go on is these charts which this site readings are the same as wallace's
thanks
mike


Charts on websites have on occasion been incorrect. I'll take Paul Spotts word over that of a chart on the web listing a head that not very many people know anything about.

Will Rogers never met a liberal.
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Will
Cochise

Zimbabwe
285 Posts

Posted - 25 Jul 2007 :  8:01:33 PM  Show Profile  Reply with Quote
Brian,

Might want to ask Paul what his CR is for sure and how he achieved it. Maybe dished pistons?

I'm 99% sure that the 7H1s are 350 heads. That's what came on the 350 in my friend's '72 LeMans. 400s used 7J2 (small valve) and 7K3 (big valve) in '72. 455s most commonly came with 7M5s, but some other casting numbers were apparently available.

Not going just off Wallace's site either. Going from core engines that I've dismantled over the years and my friend's LeMans which was all original when he bought it in '86.

That said, I agree that Bernie should be looking for some different heads though the chamber size on those 7H1s probably isn't too far out of line.

Not qualified to answer questions about engines over 425 HP.
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hugh
Cochise

USA
430 Posts

Posted - 25 Jul 2007 :  9:58:15 PM  Show Profile  Reply with Quote
Guys, I revised my post above, sorry for any confusion. I got the 7H1 and the 7L4 mixed up. Here is what is printed in my "American V-8 Engine" data book for 1972 Pontiac heads, the cc's are from McCarthy's book:

7H1 = 350 (80cc)
7J2 = 400 ?cc
7K3 = 400 (96cc)
7L4 = 455 ?cc
7M5 = 455 (114cc)
7F6 = 455 (111cc) (Trans Am)
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Brian Baker
Mongo

USA
1050 Posts

Posted - 26 Jul 2007 :  12:26:38 PM  Show Profile  Reply with Quote
An email I got from Paul today:

"Hey Brian,

I originally ran (back in 2000) 8:1 with .080 head gaskets and flat tops in the hole aprrox .020". Then I went to 9:1 with .050 gaskets, larger bore and 0 deck. The last combo was 10:1 with domed pistons. All used the same 100 cc 7H1 heads. The 501 I'll eventually build will have dished pistons.

Paul"

Don't believe everything you read on a website, especially about a head that so many people know so little about because it wasn't a performance head.

Will Rogers never met a liberal.
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hoosierboy65
Tribal Scout

USA
3 Posts

Posted - 25 Feb 2009 :  7:45:52 PM  Show Profile  Reply with Quote
quote:
Originally posted by hugh

Guys, I revised my post above, sorry for any confusion. I got the 7H1 and the 7L4 mixed up. Here is what is printed in my "American V-8 Engine" data book for 1972 Pontiac heads, the cc's are from McCarthy's book:

7H1 = 350 (80cc)
7J2 = 400 ?cc
7K3 = 400 (96cc)
7L4 = 455 ?cc
7M5 = 455 (114cc)
7F6 = 455 (111cc) (Trans Am)

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hoosierboy65
Tribal Scout

USA
3 Posts

Posted - 25 Feb 2009 :  7:51:15 PM  Show Profile  Reply with Quote
hi guys hope you dont mind me jumping in just picked up my first car to restore 69 tempest coustom.picked up a 455 to to put in it was hoping to get somr info on the 7l4 heads will i be able to get much performance out of these at least till i can pick up something better
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hoosierboy65
Tribal Scout

USA
3 Posts

Posted - 25 Feb 2009 :  7:52:29 PM  Show Profile  Reply with Quote
the 7l4 are 114 cc also
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peanut
Tribal Scout

1 Posts

Posted - 09 Mar 2009 :  10:15:19 PM  Show Profile  Reply with Quote
Hello gentlmen, Ihave 2 sets of heads im trying to find out about. the first set has a casting # 4x the next set i was toldare rocket heads with casting #670and a date of k116 and k186, i think date is nov 11&18 1966 or 1976. Ineed to know about the #670 if anyone could help me please.
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Phil
The Great White Buffalo

USA
7222 Posts

Posted - 10 Mar 2009 :  12:33:32 AM  Show Profile  Reply with Quote
Welcome peanut.

670's are complete junk. Box them up and mail them to me. I will pay for shipping. I will throw them away for you!

Seriously though, they are good heads, high compression and were used in 67. The first of the newly redesigned Pontiac head that carried through 79 in various forms.

A desireable head with good flowing intakes, large valves (intake and exhaust) however the closed chamber design was only used that year and was opened up a bit in 68.

Worth some money but nothing like round ports. If using on anything larger than a 350, you will most likely have pump gas issues as the compression is too high for the street in a 400 and out of the question in a 455 without dished pistons or a rework of the combustion chambers.

Say hello to Jeff Dunham for me!

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.

Edited by - Phil on 10 Mar 2009 12:38:48 AM
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Mr. P-Body
Running Bear

USA
2258 Posts

Posted - 10 Mar 2009 :  09:54:54 AM  Show Profile  Visit Mr. P-Body's Homepage  Reply with Quote
Peanut,

"Rocket" is an Oldsmobile term and a foreign language here...

Chamber volume MUST be measured. All the "published data" (on the net and in books) is "nominal", and not necessarily accurate. Particularly on older engines such as these, the "history" of the heads is unknown in most cases. Compression is only a major issue IF you're "pressing the edge" of the intended fuel used.

Generally, 9.2:1 will yield enough power to satisfy most. The added power gained in going to 9.5:1 from 9.2:1 is negligible, only "useful" to those pressing the edge.

Once porting begins, most "D-port" heads are the same. Chamber is the BIG difference. Get the heads that make the final static compression you're after and make the ports and valves do the job!

Jim
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fabricator
Tribal Scout

USA
2 Posts

Posted - 18 Mar 2010 :  11:19:42 AM  Show Profile  Reply with Quote
Hi Folks. New to forum. I have a question about compatability. I recently bought a '79 Firebird . It is (really) a rust free car. It has a 400 with 7k3 heads. it looks like flat top pistons . Can anyone give me an idea of the compression ratio it should have? It runs great & has a fat Lunati cam in it. Any help would be appreciated.

Randy Dufour
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bnorris_74
Crazy Horse

USA
1442 Posts

Posted - 18 Mar 2010 :  12:00:35 PM  Show Profile  Reply with Quote
If the heads and block are not milled, I'd guess around 7.6:1.
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Vid
Kicking Horse

USA
1685 Posts

Posted - 23 Mar 2010 :  01:44:46 AM  Show Profile  Reply with Quote
quote:
Originally posted by Brian Baker

...They're essentially low compression 2-barrel carb station wagon heads.



Um, Brian... I will try to NOT be offended by that comment, LOL



BTW, 4bbl and #16 heads, LMAO
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65GPER
Tribal Scout

Canada
3 Posts

Posted - 17 May 2010 :  7:48:08 PM  Show Profile  Reply with Quote
quote:
Originally posted by hugh

Guys, I revised my post above, sorry for any confusion. I got the 7H1 and the 7L4 mixed up. Here is what is printed in my "American V-8 Engine" data book for 1972 Pontiac heads, the cc's are from McCarthy's book:

7H1 = 350 (80cc)
7J2 = 400 ?cc
7K3 = 400 (96cc)
7L4 = 455 ?cc
7M5 = 455 (114cc)
7F6 = 455 (111cc) (Trans Am)

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Latech
Cochise

USA
397 Posts

Posted - 28 Oct 2012 :  8:01:10 PM  Show Profile  Reply with Quote
quote:
Originally posted by hugh

Guys, I revised my post above, sorry for any confusion. I got the 7H1 and the 7L4 mixed up. Here is what is printed in my "American V-8 Engine" data book for 1972 Pontiac heads, the cc's are from McCarthy's book:

7H1 = 350 (80cc)
7J2 = 400 ?cc
7K3 = 400 (96cc)
7L4 = 455 ?cc
7M5 = 455 (114cc)
7F6 = 455 (111cc) (Trans Am)

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