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#1
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Building a 72 400 pontiac
I'm trying to locate the parts i need to build a 9.0 to 9.5 to 1 compression 400.
I have the 7K3 96cc heads but the flat top pistons 12cc valve reliefs which only yield me 8.0 to 1. I've looked at several pistons out there but it seems they are proud of them. Any help would be appreciated. I've got to resurrect this old girl back to her prime and better. Oh 1974 GTO, 400 muncie M21 4 speed. She is going to be a fun ride when completed. thanks T |
#2
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Heads!
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1977 Trans Am,400 4 speed,numbers matching car 1979 Bonneville ,1 owner car... 1997 Trans Am convertible,LT1/auto. |
#3
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Yes, finding some heads with smaller chamber size would be a positive step. Those 7K3s would yield the compression you want on a 455, but not a 400. Look for something in the range of 72-86cc range.
Stick with flat top pistons, as they work better with the chamber design of factory heads. |
#4
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Thanks
Thanks for the info.... Any suggestions on what will work the best as far as heads would go. I see the Edelbrock's out there but not much else at a descent
affordable price. I'm probably going to have to look for something used heads to accomplish this. Single income makes things a little different... T |
#5
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Actually,
There is nothing wrong with building your engine with the 7K3's the compression will run between 8,2 to 9.0 depending upon the pistons used. With todays cheezie gas. they are very good heads. What you need to do is get the right cam to make the engine think its a 10 to one engine. I've run more than my share of Low copression Pontiacs with no problems at the Pump. Being able to use reg unledded is a trememdous advantage. Plus the engine will have more torque than any other. Are you going racing or do you want to drive and enjoy your car?
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Try calling CRUSHPROOF! 512-386-9889 |
#6
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Good Info
I've been building chevy's and Ford's and alot of the rice rockets over 20 some odd yrs and haven't built a pontiac since i was a teen. I do plan to drive this as a weekend cruiser and of course there is someone always wanting to see what kind of power there will be under the hood.
What suggestions do you have to make the 400 think it is running in the 9.5 to 10 to 1 compression range i would like to use the 7k3 heads since there in great shape. I looked at the edelbrock versions but just don't think they will perform like i would like them too( and of course the cost). I'm already getting the challenges from my Ford neighbors and want to build this car to make a few heads turn but it's going to be my weekend only ride...Any good suggestions on pontiac 400 combinations would be greatly appreciated. The muncie 4 speed will allow for several combinations on cams but i'd like to get some info from some of you guys that have built known good pontiac rumblers. Thanks guys for all the help..... T |
#7
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or just convert it to a 455 and get the best of both worlds
http://www.angelfire.com/fl4/pontiac...sspecials.html
__________________
70 GTO 462 E-Heads TKO-600 9-Inch/3.60's |
#8
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455`
Thanks Billy I'm looking for all the info on places to pick up the parts i need.
That may be an idea for sure but i may have a line on a running 455 i guess i'll wait and see what happens first. I've still got alot of panels to replace and some custom interior to get done so i have some time before the engine build, But please pass on any info on used and new performance parts to pick on my Mustang neighbors when this little lady get finished LOL.... thanks again for the info. Now to find the cam and intake that will allow me to keep the shaker hood functional. So far looking like the performer intake but any suggestions will be appreciated. thanks all T |
#9
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Hi i have 72 gto 400 with the stock 7K3 heads and had the motor rebuilt a couple years ago.It has low compression appox. 8 .2 with the extreme energy 262h cam.I find the performance and driveability for the street just fine.Its has a muncie 4 speed and 3.23 gears.I can melt the tires all day long but have not been to the track.It all depends what you are looking for and how much $$$ you want to spend.
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#10
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72 400
Thanks Concreteburner,
That is some info i can definitely use. Not that you guys haven't been alot of help. I really want this 74 GTO to sing but i'm not taking her to a track or anything but i do have a few mustang neighbors that have already set there challenges and i want them to regret it with a passion. She is a long way from being done but most of my restore's took several months to complete so i'm going to do this one better than i've ever done. I've built some cool rides in my time. Since this one belongs to me and she doesn't have a great muscle car history with the 200 hp factory spec's. I'm going to resurrect her to be a force to reckon with she's definitely going to be my only restore for myself. It took too long to find this one LOL!!! I have a guy who wants the 400 in trade with some other items i have for a running 455 but i've not decided what to do. Any more combo's out there will be appreciated but this one does look good on the desktop dyno. Thanks again T |
#11
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Thanks
Thanks guys for all the info. I've decided to go with a 455 instead of the 400.
It seems to be the one i'll get the compression ratio that I want. Now on the hunt for a 455 and soon i'll be selling the running 400. It is a 71 yr block but i haven't got the code off the back yet. Again thanks for all the help. I figure this old girl will be a great street killer in the near future. cya T |
#12
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Before you get rid of the 400 you should check out the 461 Stroker Kits. You should have the compression ratio you want with one of those. www.jbp-pontiac.com has them
__________________
Go Fast... Return... Go Fast Again... Who cares about left turns??? |
#13
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update
Well here is the latest....
Still looking for the 455 Got the rear quarter installed (tacked) Tilt column installed picked up a 74 Ventura with original 72K but was left in an old barn. the complete floor pan has rusted away. took the pedals and quarter for the gto and the front clip will also be added once i get the motor installed. unfortunately she is a six banger 3speed on the column but good for parts. I'll keep you guys up to date as she comes back to life. If you run into anyone needing the original 74 bucket seats (cloth not vinal) let me know. They will be going to ebay soon. cya T |
#14
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Thanks Jim,
A little pricey for my budget when i get the 455 built for around that in price. Thanks for the info all help is appreciated. cya T |
#15
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You do ralize...
that the 7K3's will not facilitate headers, as they have no bolt holes or even the bosses to drill them on the ends. Just FYI. Good luck "representin'" against those five litre peter beaters! lol Ron
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"The great obstacle to discovery is not ignorance...but the illusion of knowledge." Daniel J. Boorstein "Gas is STILL your cheapest thrill!" Your opinion of me is none of my business. |
#16
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Actually
Thanks Jegstek,
Actually these do have the accessory holes pre-drilled. Didn't know about the headers though. I plan a couple of side pipe exhaust on this little lady anyway so stock manifolds will do fine for my needs. Thanks for the FYI though. Lots of plans but no time to get them done LOL!!! I do plan on destroying the mustangs just to make a point LOL!!! cya T |
#17
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Actually
Thanks Jegstek,
Actually these do have the accessory holes pre-drilled. Didn't know about the headers though. I plan a couple of side pipe exhaust on this little lady anyway so stock manifolds will do fine for my needs. Thanks for the FYI though. Lots of plans but no time to get them done LOL!!! I do plan on destroying the mustangs just to make a point LOL!!! cya T |
#18
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Three suggestions that I hope will help you out-
Buy Jim Hand's book. There are several 'recipes' for Ponitac engines in there and it's especially informative for those who aren't as familiar with Pontiac engines as they compare to other makes. it's very easy reading and you'll find it comes highly recommended on these boards- Look up Cliff Ruggles (CliffR on this site)...He presently owns the car that you are trying to build.... Explore some of the other forums on these boards. You've posted this topic in what is basically a 'non Pontiac related' section so you'll get more views and advice from some of the folks that don't even look here.
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Greg Reid Palmetto, Georgia |
#19
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Thanks Greg,
That will definately he a great help. Getting into the Pontiac world again is being a difficult task. The crusher has been my enemy lately. All the parts i've been finding have already been crushed by the salvage yards. Not alot of ponitac's around the B'ham Alabama area anymore. I'll take a look and see if i can find that book. thanks T |
#20
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T,
I didn't know you were in B'ham. You have a good source of parts pretty near you, in Talledega. There's a guy there by the name of Preston. He goes by the user name on this site "thepontiacman"... He's got plenty of Pontiac parts. I've never gotten around to meeting him but I've been hearing about him for years- Before I ever even joined this site. I'm from Jacksonville, AL myself and I'm over there regularly. I've been meaning to contact Preston to take a look around his place one of these days.
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Greg Reid Palmetto, Georgia |
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