[jhein]

I have to admit, I wouldn't mind a little more power. Right now I have a bone stock RAIII. If I rebuilt it with a stroker kit, keep the #12 heads, use dish pistons to reduce the CR to around 9.5:1 to make it pump gas friendly what would I be looking at for power with let's say a 744 cam? Would that be the best choice or some other cam or other options? I'd like to get 450-500 HP.

[78w72]

curious to see what others suggest on this, but with stock heads & a smaller cam like that (224/236 ~.406 lift), is 450-500hp even possible? especially if you are using a stock intake & exhaust manifolds.

[jhein]

I guess that's really my question, what's the most HP I can get with stock heads, 9.5:1 CR and stock exhaust manifolds? I figured the heads would need porting and probably a bigger cam. I asked Butler the same question so we'll see what they say.

[jhein]

This is what Butler said:

"With stock heads and a stroker bottom end and a hyd. roller about 420-430HP is it (with a good intake and an 850cfm carb and headers)

That’s about as far as you can push with pump gas and no additional air flow.

The same combo with either a well ported iron head or an out of the box alum would make 500+HP"

This is the cam they suggested: Butler/Comp SP Street Performance Billet Roller Cam (HR) 288/294, 236/242, .521/.540, 112 LS

I don't know if the experts here will agree with that or not. But, based on that with my planned setup (stock intake, no headers) maybe close to 450? That would probably be worth it.

[78w72]

well im far from an "expert" but it sounds like stock heads & ex manifolds would kill any real advantage of doing a stroker... for about the same money you could probably get the same or more power with a set of aluminum D port heads & a roller cam & some ram air manifolds??

[jhein]

Originally Posted by 78w72

well im far from an "expert" but it sounds like stock heads & ex manifolds would kill any real advantage of doing a stroker... for about the same money you could probably get the same or more power with a set of aluminum D port heads & a roller cam & some ram air manifolds??

The stroker rebuild would be the most expensive option by far. But, I'd get a brand new rotating assembly, 61 extra CID, pump gas friendly CR and keep my stock appearance. I've already got the RA exhaust manifolds. But from a "bang for the buck" standpoint for HP increase, I think you're right.

[jhein]

Originally Posted by 78w72

well im far from an "expert" ...

BTW, when I used the word "expert" I was not taking a jab at you at all. I appreciate all advice, and pretty much everyone here knows more than me anyway.

[78w72]

Originally Posted by jhein

The stroker rebuild would be the most expensive option by far. But, I'd get a brand new rotating assembly, 61 extra CID, pump gas friendly CR and keep my stock appearance. I've already got the RA exhaust manifolds.

with aluminum heads on your current engine you would still be pump gas friendly, im sure you know but aluminum can go a full number or more over iron heads & still be ok on pump gas. the added flow of alum heads over stock heads & a good cam would be about the same HP as a stroker kit with stock heads but cheaper & easier to do than a full stroker rebuild. a factory crank is just as strong or stronger than a cast stroker crank. alum heads wont be 100% stock appearance but many guys have done a stealth look with aluminum heads by grinding off the name & painting them stock color blue.

Originally Posted by jhein

BTW, when I used the word "expert" I was not taking a jab at you at all. I appreciate all advice, and pretty much everyone here knows more than me anyway.

i didnt take it as a jab at all, just wanted to state up front im far from an expert compared to some on here but have been dealing with pontiacs/firebirds & doing most of my own work on them for 30+ years. but i will leave it to others to provide more suggestions & knowledge on this.

[Lee]

HP is misleading, even more so when dealing with motors that make much more torque than HP. People often throw away a lot of lower RPM TQ to gain a little of upper RPM HP.

What do you want the car to DO?

I've built higher compression, ported head motors that ran in the 11's. But they were not that much to just drive around.

My current motor is a low compression (8.3:1) 455, stock crappy "66" heads (huge chambers, pressed-in rocker studs), and an old P4B intake manifold. The cam is a 222/242 @ .050", low lift (.443"/.435") on a 116lsa that is happy with the stock rockers, pushrods and adjusting nuts. The cam is sort of modern version of the 744, optimized for a motor with a better exhaust system. I DO have a low-restriction exhaust, and it also has a FAST efi/ignition control system - but a well tuned HEI and Q-jet should perform just as well. The car has a 3.08 gear, a THM 350 with a stock converter, runs great on the cheapest gas I can find, and tends to run cool.

It puts 316hp/385tq to the wheels. I took it to the track recently. The trans was shifting several hundred RPM too late, and I had to launch at part throttle to keep from spinning, but it still ran 13.20. I just got some parts to address the transmission issue, and hope to do more track testing soon.

https://i.imgur.com/P0pUNqX.mp4

[66beaumont]

Originally Posted by jhein

This is what Butler said:

"With stock heads and a stroker bottom end and a hyd. roller about 420-430HP is it (with a good intake and an 850cfm carb and headers)

That’s about as far as you can push with pump gas and no additional air flow.

The same combo with either a well ported iron head or an out of the box alum would make 500+HP"

This is the cam they suggested: Butler/Comp SP Street Performance Billet Roller Cam (HR) 288/294, 236/242, .521/.540, 112 LS

I don't know if the experts here will agree with that or not. But, based on that with my planned setup (stock intake, no headers) maybe close to 450? That would probably be worth it.

400 ys stroker 9.5:1. 467. 430 hp and 550 torque. Stock heads and intake system and ram air manifolds .oh and runs on 87 octane

[jhein]

Originally Posted by 66beaumont

400 ys stroker 9.5:1. 467. 430 hp and 550 torque. Stock heads and intake system and ram air manifolds .oh and runs on 87 octane

That's the SD performance cam? I know you said stock heads, but just to confirm, no porting?

[racerboy]

Jhein
It looks like you and I are looking to do the exact same thing. My ‘70 RA Iii has less than 10k miles on it, but when the previous owner had it rebuilt on 2009, the shop he went to re-used the stock rods and some lo-performance 8-eyebrow pistons. They also put in a cam smaller than an 068. Since I was going to pull the engine to address these issues, I had a couple of threads running about whether I should stroke the original WS 400 or drop in a 428 I have in my garage.

I ultimately decided to find a 400 or 455 block, and go the stroker route with a set of aluminum heads and one of the SD Perf. cams. I’ll just bubble wrap the original block and #12 heads for now. I’ll be curious to see what you ultimately wind up doing with your combo.

[racerboy]

Originally Posted by 78w72

. alum heads wont be 100% stock appearance but many guys have done a stealth look with aluminum heads by grinding off the name & painting them stock color blue.

This is exactly the route I plan to go. Like the OP, I was considering having work done to my original #12 heads, but it seems so much easier to just go with a set of aluminum heads. I’m planning on running the stock intake (and have SD Perf. do the CNC porting) as well as the Ram Air manifolds. It will look sort of stock (I hope).


Sent from my iPhone using Tapatalk

[jhein]

Originally Posted by racerboy

Jhein
It looks like you and I are looking to do the exact same thing. My ‘70 RA Iii has less than 10k miles on it, but when the previous owner had it rebuilt on 2009, the shop he went to re-used the stock rods and some lo-performance 8-eyebrow pistons. They also put in a cam smaller than an 068. Since I was going to pull the engine to address these issues, I had a couple of threads running about whether I should stroke the original WS 400 or drop in a 428 I have in my garage.

I ultimately decided to find a 400 or 455 block, and go the stroker route with a set of aluminum heads and one of the SD Perf. cams. I’ll just bubble wrap the original block and #12 heads for now. I’ll be curious to see what you ultimately wind up doing with your combo.

Originally Posted by racerboy

This is exactly the route I plan to go. Like the OP, I was considering having work done to my original #12 heads, but it seems so much easier to just go with a set of aluminum heads. I’m planning on running the stock intake (and have SD Perf. do the CNC porting) as well as the Ram Air manifolds. It will look sort of stock (I hope).

I was leaning towards keeping the iron heads and having them ported. However, right now, I'm thinking that the Edelbrock Aluminum D port heads may be the way to go. That's going to give me the most power increase, I would probably go with the 72cc chambers that way I keep my high CR too.

The biggest problem I have right now is finding someone to build it. I want to do it this spring. All the big name people are a year or more out. I'm looking around now for someone local but nothing yet.

[napster]

Jhein & Racerboy,

I don’t know if this will help you, but here it goes.

A few years ago, I purchased a 1970 T/A that had a service replacement block. The person I bought from had the engine rebuilt and replaced the #12 heads with RA IV #614 heads. After I bought the car, the engine had to be rebuilt with less than 100 miles on it.

I decided to have the engine rebuilt with a 427 stroker kit and with the .030 overbore now have a 433 CID engine. The engine was dyn’d but I only got uncorrected numbers. 447 HP @ 5000 RPM and 535 TQ @ 3500 RPM. I figure the corrected numbers are 460 HP and 545 TQ. Compression is 9.9 to 1. All of this runs thru the oversized RAIV manifolds. My engine builder thinks long tube headers would add 30 HP.

Hope this helps.

[jhein]

Originally Posted by napster

Jhein & Racerboy,

I don’t know if this will help you, but here it goes.

A few years ago, I purchased a 1970 T/A that had a service replacement block. The person I purchased from had the engine rebuilt and replaced the #12 heads with RA IV #614 heads. After I bought the car, the engine had to be rebuilt with less than 100 miles on it.

I decided to have the engine rebuilt with a 427 stroker kit and with the .030 overbore now have a 433 CID engine. The engine was dyn’d but I only got uncorrected numbers. 447 HP @ 5000 RPM and 535 TQ @ 3500 RPM. I figure the corrected numbers are 460 HP and 545 HP. Compression is 9.9 to 1. All of this runs thru the oversized RAIV manifolds.

Hope this helps.

Yeah, that does help. Obviously different heads than what I have or may use. What cam are you using?

[napster]

Butler custom grind.

[66beaumont]

Originally Posted by jhein

That's the SD performance cam? I know you said stock heads, but just to confirm, no porting?

Yes SD cam(first version) and no porting. A jet upgraded by myself with parts from Cliff. Have not yet had a chance to get to drag strip

[napster]

jhein,

I also have a 461 stroker in a '78. Running e-heads and long tube headers and an off the shelve comp cam XR288HR. 583HP @5500 and 623TQ @ 4200. 9.5 to 1 compression.

This might help more than the other example.

[jhein]

Originally Posted by napster

jhein,

I also have a 461 stroker in a '78. Running e-heads and long tube headers and an off the shelve comp cam XR288HR. 583HP @5500 and 623TQ @ 4200. 9.5 to 1 compression.

This might help more than the other example.

Those are very impressive numbers. That's definitely more than I want or need.
How do you use that car and how are it's manners?