# Recipe for my 70 Lemans build



## 400lemans (Feb 13, 2019)




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## Old Man Taylor (May 9, 2011)

Although the question is too open ended, I still have a few suggestions. Since your rebuilding the engine (and therefore boring it), you will need new pistons. Everyone knows the major weak link in a Pontiac engine is the rods. So replace them. If you are doing all of that, you are open to upgrading to an aftermarket crank. Then you have your choice of strokes: 3.75" (400); 4.00" (428); or 4.25" which is slightly more than a stock 455. This will yield displacements from 406 to 460.

Next I would top it off with Edelbrock heads. If you need an exhaust system then you might as well use the round ports. If you have a good exhaust system that you want to rebuild, then go with the D-ports. When preparing the block use studs for the main caps instead of bolts. The cam choice will depend on what you want to optimize.


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## PontiacJim (Dec 29, 2012)

You give us little to go on at all.

First, do you have a budget in mind, can you spend $6,000 or $15,000 on an engine build?

Are you looking for a 400HP range or 750HP range?

Do you want 5 MPG's or 15 MPG's?

Do you want a street/cruising car or race car you can drive on the street?


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## 400lemans (Feb 13, 2019)

Old Man Taylor said:


> Although the question is too open ended, I still have a few suggestions. Since your rebuilding the engine (and therefore boring it), you will need new pistons. Everyone knows the major weak link in a Pontiac engine is the rods. So replace them. If you are doing all of that, you are open to upgrading to an aftermarket crank. Then you have your choice of strokes: 3.75" (400); 4.00" (428); or 4.25" which is slightly more than a stock 455. This will yield displacements from 406 to 460.
> 
> 
> Old Man Taylor said:
> ...





Old Man Taylor said:


> Although the question is too open ended, I still have a few suggestions. Since your rebuilding the engine (and therefore boring it), you will need new pistons. Everyone knows the major weak link in a Pontiac engine is the rods. So replace them. If you are doing all of that, you are open to upgrading to an aftermarket crank. Then you have your choice of strokes: 3.75" (400); 4.00" (428); or 4.25" which is slightly more than a stock 455. This will yield displacements from 406 to 460.
> 
> Next I would top it off with Edelbrock heads. If you need an exhaust system then you might as well use the round ports. If you have a good exhaust system that you want to rebuild, then go with the D-ports. When preparing the block use studs for the main caps instead of bolts. The cam choice will depend on what you want to optimize.


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## 400lemans (Feb 13, 2019)

Thanks for digging in for more specifics for my build.going back in time,I rebuilt my moms 68 catalina which took 4 years starting in boces automotive and completing with the help of my boss while working as an apprentice for him. Completing all stock except for an ordered GTO cam, no thoughts or knowledge of cams,heads,all I knew was cam,4 bl and dual exhaust.I searched for a body and found a 70 Lemans and drove and raced the hell out of that car for years ,until I was rear ended and sold the motor to a friend. Now 44 years later,I located a 70 Lemans Sport convertible and as I said I bought a good foundation block.I am older now and in a better position to do it much better and plan on it being my last project so I want to do it as great as I can.Dont want to buy a Butler and drop in,although I would love that,I want a built not bought as I have the ability and the shop. what I lack is experience in high performance as I spent my years at new car dealerships and know how to repair cars they way they were built,but spent no time doing performance upgrades other then simple procedures like air intakes,programming,ect. What do I want to do with my car?? I want it to have a great thoaty sound,nice choppy idle,tire spinng torque,highway cruise engine speed hopefully around 2200, power low to mid range,not interested in turning 5500-6500 rpm as I dont abuse my cars and would probably never horse it to that.. Thats why Im interested in a proper dyno break in and tune,so I dont have to go out and tear the streets up to get my tune right.Im thinking about this as a rough draft.. fords 9 inch GM a body axle with a 3:25 or 3:42 posi diff, performance built 350 or 400 turbo with a stall converter,say 2500 rpm? the motor 400 block,stroker kit crank and pistons,roller cam,ratio rockers,large valve pontiac heads worked or Edlebrock aluminum,so pricy for pontiacs ?? dual plane intake and a Eldelbrock 4 barrel, long tube headers,with flow master exhaust system.. Id love to come in around 10k to 12 k doing most of the work.. I have problems figuring out the perfect recipe as far as specs for each and part numbers so the whole system works together and does what I want it to do.. Thanks ,


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## PontiacJim (Dec 29, 2012)

400lemans said:


> Thanks for digging in for more specifics for my build.going back in time,I rebuilt my moms 68 catalina which took 4 years starting in boces automotive and completing with the help of my boss while working as an apprentice for him. Completing all stock except for an ordered GTO cam, no thoughts or knowledge of cams,heads,all I knew was cam,4 bl and dual exhaust.I searched for a body and found a 70 Lemans and drove and raced the hell out of that car for years ,until I was rear ended and sold the motor to a friend. Now 44 years later,I located a 70 Lemans Sport convertible and as I said I bought a good foundation block.I am older now and in a better position to do it much better and plan on it being my last project so I want to do it as great as I can.Dont want to buy a Butler and drop in,although I would love that,I want a built not bought as I have the ability and the shop. what I lack is experience in high performance as I spent my years at new car dealerships and know how to repair cars they way they were built,but spent no time doing performance upgrades other then simple procedures like air intakes,programming,ect. What do I want to do with my car?? I want it to have a great thoaty sound,nice choppy idle,tire spinng torque,highway cruise engine speed hopefully around 2200, power low to mid range,not interested in turning 5500-6500 rpm as I dont abuse my cars and would probably never horse it to that.. Thats why Im interested in a proper dyno break in and tune,so I dont have to go out and tear the streets up to get my tune right.Im thinking about this as a rough draft.. fords 9 inch GM a body axle with a 3:25 or 3:42 posi diff, performance built 350 or 400 turbo with a stall converter,say 2500 rpm? the motor 400 block,stroker kit crank and pistons,roller cam,ratio rockers,large valve pontiac heads worked or Edlebrock aluminum,so pricy for pontiacs ?? dual plane intake and a Eldelbrock 4 barrel, long tube headers,with flow master exhaust system.. Id love to come in around 10k to 12 k doing most of the work.. I have problems figuring out the perfect recipe as far as specs for each and part numbers so the whole system works together and does what I want it to do.. Thanks ,



Suggest you first purchase and read a couple of the engine build/assembly books to get an idea of rebuilding a Pontiac and what upgrades you can go with.









FAQ - General: GTO and Pontiac Reference Sources


Surprised this has not been brought up - a suggested reading list for us Pontiac enthusiasts. Let's list any books, journals, factory literature, CD's, or other printed materials tht may be of value. And, it does not have to necessarily be Pontiac specific if it can be applied to out hobby...




www.gtoforum.com





10-12K might be doable if you keep the engine conservative on what goes into it.

Butler stroker 461 kit, 9.0 compression would be first pick as bigger cubes will do the trick.

BUT, you have to decide what heads so as to get your 9.0 compression for iron heads, 10.0 for aluminum heads because you want to know what size (CC's) your head's combustion chamber will be. Then you can order pistons to match the head chamber CC's.

E-heads, or KRE (Kauffman) heads are pricey and will shoot your budget away. Iron heads will be about half, but can get good results for what you want in a street build. Nightmare Performance has a good deal and one of out members in New England is getting the Stage II set. I had my iron heads rebuilt with all new and did my own port/bowl work and it ran me $1,200 just to give you an idea of cost and those were heads I had, so buying a set of big valve heads will need to be added. But here is an option and they would be bolt-on:



Nitemare Performance | Custom-Ported Pontiac Cylinder Heads



You do not need an aluminum intake. Save money and use a factory cast Q-jet intake. Several here have recommended a Q-jet from Jet Performance if you don't care to tackle the rebuild yourself.






Rochester Quadrajet – Jet Performance Products







jetchip.com





Roller cams/lifters =$$$$$$. Don't see a need when hydraulic flat tappet will do the job and save money.

Just some basics above on engine parts. 

Trans? Why not step up to an overdrive? Go with an overdrive and you can take advantage of a better choice of rear-end gearing to make the car smoke tires yet loaf on the highway? Cliff Ruggles has a book that covers the OD transmissions for a Pontiac.

The Ford 9" would be a good choice over a 12-bolt. The 10-bolt is weak and can take a good amount of punishment, but it can also break with a lot of HP/TQ and wide tires. You can purchase a bolt-in 9" having the correct GM control arm attachments/spring pockets. Not inexpensive. I put together a 9" with my specs in mind buying piecemeal and had a shop assemble the carrier and I put it together. Price was $2,800. A complete rear would save the assembly and be ready to bolt in.

So that's a start, but do your reading/research and then ask questions as you go. 10-12K might be optimistic, but doable if you select the parts that make it possible. Start going aluminum heads, roller cam/lifters, aluminum intake/Holley, and it'll go much higher. It always seems budget WILL go over, so don't hold yourself to it.


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## Old Man Taylor (May 9, 2011)

We can certainly walk you through each step of the process. As to the rear end - I did not hurt my 10 bolt until I started racing with slicks. Even then I broke an axle, but the center section was still good. If all your looking for is tire spinning torque, then the 460 with your 10 bolt will do the trick. A torque converter with a 2200-2500 stall speed would be good. Also, you may not want to buy a turn key engine from Butler,. but they can still help you select parts to suit your needs.


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## 400lemans (Feb 13, 2019)

I really appreciate your time and suggestions.. I will get down to more reading and get back with you guys with an update.. really,thanks again.


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## Jared (Apr 19, 2013)

I'm currently working on a very similar build. Your $10 - 12K budget is doable and will get you north of 400hp with you doing the work. The costs do go up pretty quick so try and have everything planned out in advance. One word of warning, the machine shops seem to be slammed with work right now so be patient with time expectations. I just got word yesterday that my short block is ready 19 weeks after placing the order. When I started this project I had reached out to Butler and they were over a year out for an assembled engine. I have a pair of heads on order from Nitemare and they are behind as well due to storm damage to the shop several weeks ago. 

Good luck with your build. The guys on here are great with advice.


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