Actual ZL-1 Horsepower.

[Ozark]

Does anyone know the actual HP that the ZL-1 produced? Anybody taken a stock ZL-1 and flogged it on a dyno? I know the L-88 was WAY underrated and have heard real world numbers of around 560 HP for the L-88. Given the bigger cam of the ZL-1 I would think that it would better that number.

[Chevy454]

[intercom voice] Paging COPO Pete, COPO Pete to your computer, please...[/intercom voice] http://www.yenko.net/ubbthreads/images/graemlins/biggthumpup.gif

[68TopStock]

Just get a copy of the July '04 Chevey Rumble, its got Petes dyno test against a F*rd.

[Mr70]

In the June 2004 MuscleCar Enthusiast,Petes 427 Dynoed at 465HP & 426lb-ft of Torque.They bested it one last time by installing headers to reach 508.6HP & 470lb-ft. torque.
MERCY! http://www.yenko.net/ubbthreads/images/graemlins/burnout.gif

[Ozark]

Engine dyno or chassis dyno? Through the mufflers? I recall the L-88 numbers I gave were at the flywheel with open headers. Thanks for the replys guys.

[COPO PETE]

Mr 70's is correct. I did build one and tore down in Michigan for the "Certified Stock" thingy. I should have decked the block as it was 40 thousands tall and the pistons ended up sitting in the hole too much! Actual compression when they worked it out was 10:8 to one http://www.yenko.net/ubbthreads/images/graemlins/no.gif It was flywheel horsepower, but also on what they call a "sad dyno" as apposed to a happy dyno, meaning, it is conservative. Still was enough to propell the car to 12.0's on more than one occasion on polyglas tires. Heads were NOS and never touched other than a valve job. Pistons were stock TRW units.
Peter

[firstgenaddict]

If I am not mistaken there was a dyno run in 1969 in Hot Rod on the ZL-1. I don't remeber what they said the HP was but I will go and try to find the magazine this weekend.
JAG

[68TopStock]

Sorry, goofed up on which magazine it was, great job Pete.

[William]

Bill Porterfield did just this about 15 years ago with a carefully rebuilt engine from ZL1 #26.

All accessories, production 375.7 HP
exhaust manifolds, Camaro
chambered exhaust system,
36 degrees timing

As above with 2-1/8" headers 418.9 HP
replacing the manifolds

Air cleaner, alternator, AIR 447.2 HP
pump removed

Carb re-jetted, timing set 444.2 HP
to 39 degrees

Chambered exhaust system 523.6 HP
removed

Note the chambered exhaust system everybody craves cost almost 80 hp.

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

[SMGCO]

Great point about chambered exhaust. However, I've seen aftermarket stainless systems advertised with 2 1/2 or even 3" mandrel bending that might be o.k.

[GMH454]

Had the joy of a A/Prod Vette with crate L-88 several years ago. I asked the guy I bought it off about the horsepower and said his engine was built for torque, the engine builder had told him it was 550lbs.
It drove like it, at around 4800-5200 it would break the tyres loose (Big 10" racing wheels). That was not on the gear change but on accelerating up thru the rev range, in third that's around 130mph with a nice twitch just to make sure you are paying attention.
Junior Johnson once said "horsepower sells cars....torque wins races"
When Tonawonda (forgive the spelling ) closed the NCRS did a feature on it and asked the guys there what the L-88s dynoed at, they said around 510hp, on the engine stand.

[GRB]

Does anybody know if the GMMG chambered exhaust is as restrictive as the OE GM exhaust? If it is I've got to start making plans to get the GMMG system off my 02 ZL1. Since I last posted we have decided to put a SC on the car. Of course when we dyno the car with the Kooks headers open and then closed we will know for sure. Something tells me we should go ahead and plan for a different exhaust system now. Any thoughts?? And I don't care for the duals that dump over the rear axles. Gotta go all the way out the back for me.

[SMGCO]

I don't think there is any comparison between the old OEM chambered exhaust and the gmmg chambered exhaust. The old exhaust was crimped at the bends and was down to less than 2" in many areas. Our gmmg exhaust is mandrel bent ( ie, smooth bends ) and fits perfectly. Call Murphy and discuss it with him. He thought everything on our cars through with ultimate performance in mind. However, you might want to talk to Porterfield out the dual cutout he has on car #1. Barry at Quick Time Performance can help you also.
What rear end gear ratio do you have in your car ? The 4.56's in mine really woke it up. Any more power and getting traction is not possible without drag radials or dot slicks.

Regards, 02-#47 zl1 ( c5r ) http://www.yenko.net/ubbthreads/images/graemlins/naughty.gif

[Chevy454]

I visit quite a few LS1 sites, and they all seem to rave about the GMMG chambered system. In fact, they're doing a group purchase over at LS1tech right now. Everyone used to want the LoudMouth exhaust, but now everyone seems to be ditching it in favor of the GMMG.

The GMMG chambered is nothing like the restrictive chambered on the first Gens...in fact, when I was replacing the chambered on our '69 I looked into trying to retro-fit the GMMG system.

Are you still running the 10bolt?

[GRB]

We will know for sure when we hit the dyno. Rear is a Moser 4:10. Traction will be the #1 problem. I don't know what pic will show up. I think I really screwed this one up. The rear end may be a Strange...we have changed so many things I can't keep up!! I'll find the right pic.....maybe.

[GRB]

One more try....

[GRB]

Seems like we had to get Strange to make some special axles so the wheels would be properly hub centric and NHRA legal...but that's a whole nother argument. The pic is of my optional set of tires. The OE Goodyears are on Fikse Profil FM 10s.

[GRB]

This retardation is killing me....

[GRB]

Made another change on #51. Going with a solid roller and a little different profile for the Pro Charger. I don't think I'll have to worry about the new Harrell edition. http://www.yenko.net/ubbthreads/images/graemlins/burnout.gif

[Belair62]

hmmmm...the new Day 2 !