[mgarblik]

Originally Posted by Lee

I do not believe I have ever seen a 600hp Pontiac street engine that did not have headers.

I will give you that, sure. Can't point to a particular one either. But it can be done with moderate effort if one wish's to. It would consist of your basic 462 CU in carefully blueprinted engine with aluminum heads, making 650 HP on the dyno. There are hundreds of those builds here on PY. Take headers off, put long branch manifolds on, lose 35 HP or so. You now have a street engine for cruises and power tour type duty making 600-615 HP that would be quiet, easy to drive over a speed bump and very streetable. Drop the HP number to 550 HP and you have a very docile street engine with exhaust manifolds and a 1000 RPM idle. Point was exhaust manifolds and the inability to get them is a driver in the aftermarket head world for Pontiac. If your married to D ports, your choices are very limited. So prices are high. Iron replacements would be a game changer and alter the market. They would steal 25-35% of the aluminum market IMO, and force the prices of aluminum heads down to where they belong. Competition and choice a
ALWAYS levels the playing field.

[NeighborsComplaint]

Originally Posted by Murf

So what is the answer? A vast conspiracy against the Pontiac community?


Sent from my iPhone using Tapatalk Pro

Pretty much sums it up. Apparently the entire automotive world believes Pontiacs had poor-flowing heads in stock form and will pay the price for incremental improvement.

[Dragncar]

Originally Posted by NeighborsComplaint

How?

Per Wallace Racing Calculator w. 4.30 gasket bore dia.:

Your displacement is 464.62 CID
The Compression Ratio is: 11.77

No way that should work on pump gas even with aluminum heads.

Yes it will, its all about the cam. Building a 11-1 engine right now and a 11.5-1 540 after that, 91 CA piss gas. Call Scott Brown, he will hook you up.
A LOT has changed the last few years with cams.

[Steve C.]

"First, a word about factory Pontiac heads in general: Pontiac heads were originally designed to get heavy cars up and moving. As such, they emphasize low-end torque over top-end power. Pontiac port volumes are roughly equivalent to a 350 Chevy small-block, yet most Pontiac engines are at least 50 ci larger. When it comes to porting the factory Pontiac heads, H-O Enterprises' Ken Crocie, a recognized Pontiac expert, says "You can't make a Pontiac head big enough. You can make it wrong, but not too big."

From Hot Rod magazine
https://www.hotrod.com/articles/hrdp...pontiac-heads/


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[NeighborsComplaint]

Originally Posted by Dragncar

Yes it will, its all about the cam. Building a 11-1 engine right now and a 11.5-1 540 after that, 91 CA piss gas. Call Scott Brown, he will hook you up.
A LOT has changed the last few years with cams.

Scott Brown lives down the street from me. By complete coincidence, he drives a brown truck for UPS. We chatted about your camshaft but he didn't have a clue what I was talking about. I then dialed 1-800-CAM-SHAFT but got some sexy sounding lady named Camille who turned out to be a guy. Seriously dude, who is your Scott Brown and how would I call him? A simple "Call him at XXX-XXX-XXXX" is always better than an easter-egg hunt. BTW, by all reports he seems to have disappeared since his last know where-abouts at Straightline Performance in Okemos MI. (Yes, Google is a friend of mine.)

Honestly. I'm more than a bit hesitant to go with a new roller cam of unproven design with questionable roller lifters and a higher stall convertor to suit the new camshaft. I've driven this car with 11.5:1 iron heads, Comp 305 Magnum cam, single plane intake, 3500 stall convertor and 4.56 gears out back. It was at times satisfying, but never a pleasant experience.

Edelbrock designed 2 chamber sizes to accommodate 400 and 455 displacement motors for good reason. I questioned the guy here on the board who sells the 72cc ProComp heads through eBay. Without even discussing a camshaft profile to bleed off compression, he said "no way unless you want to run an E85 fuel system." This is not a viable option to me given the fuel system corrosion issues that long term use of E85 develops.

I just wanted to bolt-on some better heads using what I currently have which is docile enough to drive anywhere, any weather, and still provide a rush. Not saying I doubt your claim but I have come to the conclusion that the new heads are a pipe dream and in reality offer little benefit despite the bigger flow numbers, given the cam I am currently running .

[pastry_chef]

Originally Posted by NeighborsComplaint

How?

We built a pump gas 455 using 72cc chambers, custom Ross 20 cc piston dish.

13:1 CR on pump gas?
Only at high altitude or someone doesn't know how to correctly measure / calculate (this happens all the time with pro builders).
Some burettes are off by several CC.. for high accuracy get a class-A, expect to pay a few hundred $$.

[Steve C.]

Plus the obvious, the chamber volumes can vary on one set of heads along with the method of measuring. For interest the last time my Edelbrock heads were off the engine I had two different machine shops measure one chamber each.
I watched each time and never said a word as each fellow did it slightly different. One reported 77 cc's and the other was 79 cc's.


.

[Dragncar]

Originally Posted by NeighborsComplaint

Scott Brown lives down the street from me. By complete coincidence, he drives a brown truck for UPS. We chatted about your camshaft but he didn't have a clue what I was talking about. I then dialed 1-800-CAM-SHAFT but got some sexy sounding lady named Camille who turned out to be a guy. Seriously dude, who is your Scott Brown and how would I call him? A simple "Call him at XXX-XXX-XXXX" is always better than an easter-egg hunt. BTW, by all reports he seems to have disappeared since his last know where-abouts at Straightline Performance in Okemos MI. (Yes, Google is a friend of mine.)

Honestly. I'm more than a bit hesitant to go with a new roller cam of unproven design with questionable roller lifters and a higher stall convertor to suit the new camshaft. I've driven this car with 11.5:1 iron heads, Comp 305 Magnum cam, single plane intake, 3500 stall convertor and 4.56 gears out back. It was at times satisfying, but never a pleasant experience.

Edelbrock designed 2 chamber sizes to accommodate 400 and 455 displacement motors for good reason. I questioned the guy here on the board who sells the 72cc ProComp heads through eBay. Without even discussing a camshaft profile to bleed off compression, he said "no way unless you want to run an E85 fuel system." This is not a viable option to me given the fuel system corrosion issues that long term use of E85 develops.

I just wanted to bolt-on some better heads using what I currently have which is docile enough to drive anywhere, any weather, and still provide a rush. Not saying I doubt your claim but I have come to the conclusion that the new heads are a pipe dream and in reality offer little benefit despite the bigger flow numbers, given the cam I am currently running .

scotty.brown@ymail.com
616-499-6223
Its best to e mail him. Scott is well known in the Pontiac racing world as a cam/parts guy. He is great to deal with and has a lot of experience.
I am selling a cam right now, its too big for you but it was on a 12.3CR engine with 93 octane and it did not ping. Its not one from Scott, just a modern pump gas cam.
You will have no problem running 11-1 with aluminum heads with the right cam. You can push it higher but things need to be right. Iron heads are a different deal. 11.5 is too much for pump gas period.
I run 9.3 CR with iron heads and run 10.80s, it can be done.
Just get ahold of Scott, tell him your situation and he will point you in the right direction and won't try and sell you a bunch of stuff you do not need.

[Dragncar]

I know a guy who has a Ford and runs 13-1 in California with 91 octane. Its a custom cam from Bullet.

[Steve C.]

Dragncar can we presume the proposed 11:1 compression is with the 'modern' heart-shaped combustion chamber design that will allow a higher compression than the older 'bathtub' design ?



.

[NeighborsComplaint]

Originally Posted by Dragncar

scotty.brown@ymail.com
616-499-6223
Its best to e mail him. Scott is well known in the Pontiac racing world as a cam/parts guy. He is great to deal with and has a lot of experience.
I am selling a cam right now, its too big for you but it was on a 12.3CR engine with 93 octane and it did not ping. Its not one from Scott, just a modern pump gas cam.
You will have no problem running 11-1 with aluminum heads with the right cam. You can push it higher but things need to be right. Iron heads are a different deal. 11.5 is too much for pump gas period.
I run 9.3 CR with iron heads and run 10.80s, it can be done.
Just get ahold of Scott, tell him your situation and he will point you in the right direction and won't try and sell you a bunch of stuff you do not need.

Thanks. I'll give him a call and discuss . Thanks.

[krisr]

Originally Posted by NeighborsComplaint

How?



Per Wallace Racing Calculator w. 4.30 gasket bore dia.:



Your displacement is 464.62 CID

The Compression Ratio is: 11.77



No way that should work on pump gas even with aluminum heads.

Why not? My 400 is at about 11.5-11.7:1. I cut my Edelbrock round ports down to 59cc with a flat top piston but opened the reliefs up to suit piston/valve. It runs just fine on Australian piss gas. Running on E85 makes no difference either either. A lot has changed since the 70s. It still traps 120mph at full weight too and is a street car.

[Dragncar]

Originally Posted by Steve C.

Dragncar can we presume the proposed 11:1 compression is with the 'modern' heart-shaped combustion chamber design that will allow a higher compression than the older 'bathtub' design ?



.

Yes, High Ports. The 11.5-1 engine is old style E heads and a generic 32cc dish. Scott tells me it will not ping with the right cam. I have to trust his call.

[slowbird]

Why push the compression that little bit? How much power you guys think is there going from high 10:1 to mid 11:1? Is it worth the potential issues? Is the cam a good fit or is it a compromise on the higher compression engines so they don't ping?
Fwiw i was 10.8 on my pump gas engine and made just shy of 900hp, and i wouldn't want to push it any more than that nased on my experience.

[Steve C.]

Power losses from reducing compression ratio?

https://forums.maxperformanceinc.com...87#post5858987

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[Dragncar]

Originally Posted by slowbird

Why push the compression that little bit? How much power you guys think is there going from high 10:1 to mid 11:1? Is it worth the potential issues? Is the cam a good fit or is it a compromise on the higher compression engines so they don't ping?
Fwiw i was 10.8 on my pump gas engine and made just shy of 900hp, and i wouldn't want to push it any more than that nased on my experience.

Its a known fact that with aluminum heads you need 2 full points of compression to equal the power of iron because of heat loss. heat=energy and that transfers to horsepower.
I am at 9.3 right now and am going a bit less than 2 full points 10 11-1 CR but will make far more power because of head flow.(actually a bit less than 11-1)
Marcella got just shy of 1000HP on pump gas with one of Scotts cams. Its a proven track record. You think I am going to question them ? You have posted that you don't trust Scotts calculations and by your post I believe you don't.
I am at 9.3 with old bathtub chambers on the HOs with a used cam I just bought off E Bay, old school cam with not much thought on my part. So I am going just over 2 full points higher CR to 2.2 points, 11.5. Big deal, it will have a cam designed to get it done and the only thing I have to decide is do I want to go aggressive and shoot for 900HP or a bracket cam, easy on parts and live with 825-850 HP.
That engine is a ways off, have the parts but its a big project. The 461 is my focus right now.
Over here in the street section Cliff does really well with higher CR street engines with the right cam and true flat tops. That what the 461 is, flat tops and 80cc High Ports. Should be a perfect combo IMO. Zero deck, plenty of quench.

[slowbird]

Originally Posted by Dragncar

Its a known fact that with aluminum heads you need 2 full points of compression to equal the power of iron because of heat loss. heat=energy and that transfers to horsepower.
I am at 9.3 right now and am going a bit less than 2 full points 10 11-1 CR but will make far more power because of head flow.(actually a bit less than 11-1)
Marcella got just shy of 1000HP on pump gas with one of Scotts cams. Its a proven track record. You think I am going to question them ? You have posted that you don't trust Scotts calculations and by your post I believe you don't.
I am at 9.3 with old bathtub chambers on the HOs with a used cam I just bought off E Bay, old school cam with not much thought on my part. So I am going just over 2 full points higher CR to 2.2 points, 11.5. Big deal, it will have a cam designed to get it done and the only thing I have to decide is do I want to go aggressive and shoot for 900HP or a bracket cam, easy on parts and live with 825-850 HP.
That engine is a ways off, have the parts but its a big project. The 461 is my focus right now.
Over here in the street section Cliff does really well with higher CR street engines with the right cam and true flat tops. That what the 461 is, flat tops and 80cc High Ports. Should be a perfect combo IMO. Zero deck, plenty of quench.

What engine did Marcells build that cane close to 1000hp on pump gas? If you want 11.5 go far it i didn't say don't do it. Just how much extra do you think that's going to add? Cliff gets away with it because the engines don't have high VE%/high cylinder pressure. Also you're at sea level with crap CA pump gas why even push it your luck? Higher elevation/crappy air can get away with more compression.
Hope you get your 461 running this year

[Dragncar]

Originally Posted by slowbird

What engine did Marcells build that cane close to 1000hp on pump gas? If you want 11.5 go far it i didn't say don't do it. Just how much extra do you think that's going to add? Cliff gets away with it because the engines don't have high VE%/high cylinder pressure. Also you're at sea level with crap CA pump gas why even push it your luck? Higher elevation/crappy air can get away with more compression.
Hope you get your 461 running this year

The Pro Port Build. Its was on Yellow Bullet. Maybe someone can post a link. I don't remember the exact CR on that engine.

[slowbird]

Originally Posted by Dragncar

The Pro Port Build. Its was on Yellow Bullet. Maybe someone can post a link. I don't remember the exact CR on that engine.

Marcella didn't build that!

[slowbird]

Just a fwiw since it was brought up in another post that it's a proven fact that alum needs 2pts more compression here is a very good article comparing alum vs iron. About as apples to apples as you're going to get
https://www.hotrod.com/articles/ccrp...er-heads-test/