[Ramairnacho]

I have a 1970 ra3 formula who with #13 heads that has been rebuilt stock about 30 years ago and engine never started. I need To go through it again. It bored .20 over stock. The heads aren't correct but I had them rebuild harden seats and slightly bigger value openings too. It's all new springs stainless ect.i bought a set of number 12 date coded for car and thinking of running those. If I decide to do that will I need dish pistons, thinking of new rods too because stocks probably need arp bolts pressed in. My harmonic balancer probably old too. Is roller cam actually worth the extra cash and is it efficient and reliable? I have no plans on racing my car. It's a stock build with stock carb. And will have rebuilt transmission. I do want about 400 hp. Which I think I got with these #13 worked heads but not sure. I also want to do a stock transmission rebuild transmission code is pq and them add a road race posi unit and go from 331 to 307 or 273. I think 273 will be more freeway friendly but I don't know. Need some modern knowledge. I'm not building a race car basically a stock built. Advise please .

[steve25]

To make 400 Hp with either set of your heads you have in basically stock form is going to take a cam bigger then the common RA4 grind in terms of using a D port head.
And to get that 400 hp you will need to run a cam of .550” lift.


Rear gear wise you should note that from 1968 1/2 to 1970 when this size cam was used in a 400 HIGH compression motor the factory mandated 3.90 rear gears and also no A/C could be ordered.

My suggestion would be that since your doing a top to bottom rebuild anyway then get a stroke kit such that you will have at least a 430 cid motor and then you can have your 400 hp and run a more street friendly rear gear ratio.

You did not mention if you where willing to run headers, but with any motor of 400 cid or better that will buy you 15 to 20 additional Hp right there.

[Jay S]

There have been several pump gas 400s with stock heads, hydraulic flat tappet cams, with RA manifolds that made right around 400 HP. I recall one made 403HP and 480 TQ, and another made 420HP. Bullet cam and a Lunati, both mild HFT’s.

https://forums.maxperformanceinc.com...ight=Christmas

I would not want a taller gear than a 3.08.


A hydraulic roller cam is really not more dependable than a good hydraulic flat tappet cam with quality parts and machining. With some careful chosen parts, I did put money on the flat tappet lasting longer. HR cam can make more average power and there is no break in period, both nice features, best too pick out quality HR parts just like a flat tappet.

[Half-Inch Stud]

Yea, Stroke rotating kit from Butler for that block, and 400 hp comes easy while keeping the rpms in reason. Aim for the 2.73:1 ( a very fun ratio on the highway!).

Flat HYD cam 5-8* smaller than my 12.2 Sig will do it.

Built a couple PQs, Protect the Tag's paint, while cleaning the case and match the PQ paint stencil on the Bell HSG RH side.
Several paragraphs saved to say get the " Transgo th400 1-2 shift kit". STOCK conv is your friend with 455+2.73:1 rear !

[Formulajones]

Would be a neat build. 400hp is doable, would make a fun street car.

When I built my 70 RA III many years ago I kept it at stock specs with a few little tricks so the car would fall into the Pure Stock rules. I have fun racing it but it's primarily my daily driver.

With that said I had to keep compression pump gas friendly (91 octane) so I did have the flat tops machined for a slight dish. I don't remember the CC off the top of my head but with the #12 heads I ended up with 10.13:1 compression. I run the factory 068 camshaft per rules and it's been fine on pump gas for the last 25+ years. It's gone a best of 12.70's at 106 mph but usually runs very low 13's in the heat with 3.31 gears. The combo really could use more gear but it's a driver first, fun car to race second.

My guess is it probably makes around 350-370hp at the flywheel. Made 301 at the tire on a chassis dyno. So not the 400 hp you're looking for but for what it is it's a ball to drive. If I strayed from the rules a bit 400hp is doable with this setup with a cam change and a few tweaks.

https://youtu.be/er1z7PpqsnY

[vertigto]

Agree with @Jay S...those numbers are my build.

[Ramairnacho]

Originally Posted by Formulajones

Would be a neat build. 400hp is doable, would make a fun street car.

When I built my 70 RA III many years ago I kept it at stock specs with a few little tricks so the car would fall into the Pure Stock rules. I have fun racing it but it's primarily my daily driver.

With that said I had to keep compression pump gas friendly (91 octane) so I did have the flat tops machined for a slight dish. I don't remember the CC off the top of my head but with the #12 heads I ended up with 10.13:1 compression. I run the factory 068 camshaft per rules and it's been fine on pump gas for the last 25+ years. It's gone a best of 12.70's at 106 mph but usually runs very low 13's in the heat with 3.31 gears. The combo really could use more gear but it's a driver first, fun car to race second.

My guess is it probably makes around 350-370hp at the flywheel. Made 301 at the tire on a chassis dyno. So not the 400 hp you're looking for but for what it is it's a ball to drive. If I strayed from the rules a bit 400hp is doable with this setup with a cam change and a few tweaks.

https://youtu.be/er1z7PpqsnY

Mine is a formula 400 1 of 293 and im.too scared about stroking it and blowing up block.and boring it .60 over. I was even hesitant on .20 and requested honing. I did a 2.5 year date code find of missing sub parts and did it. Local.shop and friend are telling me roller cam, roller lifters,I want forged rods and roller tips too. With custom.dish pistons and a .40 quenche. Hardened value sears then other guts are saying just eliminate all roller stuff. I have a standard 331 and on freeway it will be at about 3k at 70 mph. So im.worried about that too. Maybe just stock build and dish pistons add zinc. Yes im.confused and don't plan on racing it. I want to built it and give it to my only daughter as it was her father's and grand fathers

[Mister Pontiac]

Originally Posted by Ramairnacho

Mine is a formula 400 1 of 293 and im.too scared about stroking it and blowing up block.and boring it .60 over. I was even hesitant on .20 and requested honing. I did a 2.5 year date code find of missing sub parts and did it. Local.shop and friend are telling me roller cam, roller lifters,I want forged rods and roller tips too. With custom.dish pistons and a .40 quenche. Hardened value sears then other guts are saying just eliminate all roller stuff. I have a standard 331 and on freeway it will be at about 3k at 70 mph. So im.worried about that too. Maybe just stock build and dish pistons add zinc. Yes im.confused and don't plan on racing it. I want to built it and give it to my only daughter as it was her father's and grand fathers

Love this!

I'm curious, why not just fire it up as is? I understand it sat for a number of years, but if it was never fired after a thorough rebuild, I say why not try?

I know others will recommend against this idea, and of course it's your decision. But I would certainly try first.

A good pre-oil, some new cam break-in lubrication on the lobes (since it's HFT), and spray a bit of oil in the cylinders to free up the rings, then rotate it over by hand a number of times in the process. When you're satisfied it will spin, hit the starter!

I have fired and driven many a 'stock' engine that has sat like this for decades. I wouldn't hesitate to try and fire yours as is.

Worst case, you have to pull it and rebuild it. You're talking about doing that anyway. Why not save the money up front and give it a shot? You may just have a running/driving car next week?!

Incidentally, the 428 in my wagon was fired up after a 42 year slumber. And it wasn't exactly properly 'pickled' when first stored. It hasn't been apart since Pontiac built it in 1967. Sure, it needs rebuilt, but it has needed that rebuild for the last 15,000+ miles. Eventually I'll get there...

Best of luck!

[jhein]

As mentioned, I would think about a mild stroker. It sounds like you have a solid block/foundation. So a few extra HP won't stress it. A cast stroker crank is not crazy expensive.

But the real reason is the way you want to use it. If you want to stick with the stock tranny, and you want cruise at 70 mph, that 3000 rpm will get old fast. A stroker will allow you to tolerate a taller rear gear better. I think at the very least you'd want a 3.08 or really even a 2.73 or 2.56? With my rear at 3.31 and TKX OD at .81, I have a final drive of 2.68. I can do 75 mph at about 2600 rpm and 70 mph at about 2300 rpm. It's comfortable, but I wouldn't do any less if that's how you drive all the time.

So what I think I understand is that you want have this car as a daily driver. If that means regularly cruising at 70 mph, then what you really need is a OD trans.

But I also understand your desire to keep it all original. So there's your dilemma right there.

[Formulajones]

Originally Posted by Ramairnacho

Mine is a formula 400 1 of 293 and im.too scared about stroking it and blowing up block.and boring it .60 over. I was even hesitant on .20 and requested honing. I did a 2.5 year date code find of missing sub parts and did it. Local.shop and friend are telling me roller cam, roller lifters,I want forged rods and roller tips too. With custom.dish pistons and a .40 quenche. Hardened value sears then other guts are saying just eliminate all roller stuff. I have a standard 331 and on freeway it will be at about 3k at 70 mph. So im.worried about that too. Maybe just stock build and dish pistons add zinc. Yes im.confused and don't plan on racing it. I want to built it and give it to my only daughter as it was her father's and grand fathers

Mine is another one of those 293. I figure I only live once, so I'm having fun with it If something happens I'll rebuilt it again. Yes with the 3.31's I keep a 28" tire on it and it's just under 3000 rpm at 70. I've been driving it like that for almost 30 years with long cross country trips mixed in. It's been perfectly fine. Sometimes I'll even cruise 75 mph on the longer desert stretches where the limit is 75. It's been perfectly happy. Gets 17 mpg if I keep it at 70.
It'll be my sons car one day. I figure before then I might be doing a bigger engine for it and stash the original. Keep the daily driver aspect of the car but make it faster. Sometime when all the other cars stop asking me for things.

[geeteeohguy]

Originally Posted by Mister Pontiac

Love this!

I'm curious, why not just fire it up as is? I understand it sat for a number of years, but if it was never fired after a thorough rebuild, I say why not try?

I know others will recommend against this idea, and of course it's your decision. But I would certainly try first.

A good pre-oil, some new cam break-in lubrication on the lobes (since it's HFT), and spray a bit of oil in the cylinders to free up the rings, then rotate it over by hand a number of times in the process. When you're satisfied it will spin, hit the starter!

I have fired and driven many a 'stock' engine that has sat like this for decades. I wouldn't hesitate to try and fire yours as is.

Worst case, you have to pull it and rebuild it. You're talking about doing that anyway. Why not save the money up front and give it a shot? You may just have a running/driving car next week?!

Incidentally, the 428 in my wagon was fired up after a 42 year slumber. And it wasn't exactly properly 'pickled' when first stored. It hasn't been apart since Pontiac built it in 1967. Sure, it needs rebuilt, but it has needed that rebuild for the last 15,000+ miles. Eventually I'll get there...

Best of luck!

This would be my move, seeing the purpose of the car. Huge positive it was built before parts and cam qualities took a steep dive. The 389 I rebuilt 42 years ago is STILL in my '65 GTO, and still runs well and the parts 'didn't go bad'. Lube it up, bore scope if needed, re-seal/replace any dried out gaskets, and run it!

[b-man]

At the most I might buy an inexpensive bore scope and check for rust on the cylinder walls through the spark plug holes. Being in Southern CA I doubt that you’re going to see anything bad inside the cylinders. If it all checks out prime it with an oil pump priming tool and fire it up and run it.

If it ain’t broke don’t fix it, use your hard earned dough for things the car really needs.