4-30-20 day for the 430 CanAm aluminum big block Chevy

[William]

I doubt any production ZL1 engine got near 575 hp. We worked with Bill Porterfield back in the '90s on a ZL1 dyno comparison. With a good tune up, open headers, no AIR pump, air cleaner or alternator it did 523 hp.

http://www.camaros.org/copo.shtml

Camaro High Performance has rebuilt several. With racing oil and modern rings, they see 550+hp.

[Flying Undertaker]

Originally Posted by William

I doubt any production ZL1 engine got near 575 hp. We worked with Bill Porterfield back in the '90s on a ZL1 dyno comparison. With a good tune up, open headers, no AIR pump, air cleaner or alternator it did 523 hp.

http://www.camaros.org/copo.shtml

Camaro High Performance has rebuilt several. With racing oil and modern rings, they see 550+hp.

I just had my '69 ZL-1 engine built by Brian Tilburg at Tilburg Racing in Trout Run, PA. All original 052 engine block that was bored .030 by previous owner. All NOS GM internals used, even .030 over GM pistons. Dynoed in Apr. 2019 (2nd pull) at 601 hp @ 6700 rpm limit that I had specified because of the age and rarity of the block. Brian said that the camshaft was still pulling hard, and had not reached its peak on the curve. He said it would have maybe 15-20hp more by 7300, as he had done several ZL-1's for NHRA Stock Eliminator AA/SA cars before. Race break-in oil and modern rings used. I have both dyno sheets. Same conditions as one stated above; good tune up, open headers, no air pump, no air cleaner or alternator!

[EZ Nova]

Originally Posted by Flying Undertaker

I just had my '69 ZL-1 engine built by Brian Tilburg at Tilburg Racing in Trout Run, PA. All original 052 engine block that was bored .030 by previous owner. All NOS GM internals used, even .030 over GM pistons. Dynoed in Apr. 2019 (2nd pull) at 601 hp @ 6700 rpm limit that I had specified because of the age and rarity of the block. Brian said that the camshaft was still pulling hard, and had not reached its peak on the curve. He said it would have maybe 15-20hp more by 7300, as he had done several ZL-1's for NHRA Stock Eliminator AA/SA cars before. Race break-in oil and modern rings used. I have both dyno sheets. Same conditions as one stated above; good tune up, open headers, no air pump, no air cleaner or alternator!

Ya you would have probably made more power 5-700RPM more. Those cam were rumored to pull well into the 7500/7800 RPM range, just not sure they were making more power or just hanging on better without the drop?

I looked at my ZL1 dyno sheet, @ 6700 I was at 785.1 Hp but it should have been higher. And you "probably" left 50 or so Hp on the table with you deal using the GM piston design and not pulling to 73/7500 range. Modern piston with 1/16 rings or better rings and not the 5/16 would have picked it up nicely too.

THEN one can look at the heads/valves and see what "could" be found there? I don't know what you did with your stuff, like better modern valve, back cut and valve job, but there is POWER there too.

[Flying Undertaker]

Originally Posted by EZ Nova

Ya you would have probably made more power 5-700RPM more. Those cam were rumored to pull well into the 7500/7800 RPM range, just not sure they were making more power or just hanging on better without the drop?

I looked at my ZL1 dyno sheet, @ 6700 I was at 785.1 Hp but it should have been higher. And you "probably" left 50 or so Hp on the table with you deal using the GM piston design and not pulling to 73/7500 range. Modern piston with 1/16 rings or better rings and not the 5/16 would have picked it up nicely too.

THEN one can look at the heads/valves and see what "could" be found there? I don't know what you did with your stuff, like better modern valve, back cut and valve job, but there is POWER there too.

EZ Nova: That's some nice power for the ZL-1 Combo. Mine was totally stock, no headwork, ALL NOS GM factory stock internals with stock stroke and a .030 overbore. I was very happy with the results as it will be a trailer queen. If I were building one for power, I'd use a new ZL-1 block with some aftermarket heads with
headwork, pocket porting, etc., a bigger cam and a holley dominator! Don.