koki345

Some have suggested that GM has "finally caught up" to where they were in 1969 by producing a car that's as fast as the ZL1 powered Corvettes (2 of which I believe were actually sold to the public.)

In truth, the new Z06 is a much faster car. (It also runs perfectly on relatively low octane, unleaded gas, meets all modern emissions standards and gets 16 city/26 highway MPG).

The ZL1 produced 376 SAE NET HP as installed in the vehicle. As such, is was a low 13 (and arguably a high twelve) second car.

The following links and road test expose the myths behind the ZL1 legend. The only documented examples that ran in the tens, elevens or twelves were modified. The 10 second car, which formed the basis of the "legend," was actually a heavily modified, purpose built drag car, the details of which remain sketchy at best. (I'm not "bashing" the ZL1 here; I am simply separating fact from fiction.)

Also consider that ZL1s were stripped cars. Luxury options weren't available with the ZL1 (or L88). ABS, traction control, etc. didn't even exist at the time.

Hib Halverson probably sums it up best in his article comparing the 2002 (405 SAE NET HP LS6) Z06 to the ZL1. Open and scroll down to bottom of article:

http://www.c5registry.com/2k2z06/index.htm

The following link includes the detailed dyno test results for Bill Porterfield's ZL1, the results of which are referenced in the C&D road test below. The 524 Gross HP figure was achieved with no engine accessories, no air cleaner, optimal tuning and open long tube headers.:

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

tomato

You are rught, but it really wasn't that hard to get the old big blocks to run down in the 11's and even 10's. What we don't have today are the great COPO dealers like Yenko and Nikki. I have an issue of Hot Rod mag (I thing it's Hot Rod) buried somewhere in my attic with an old advertisement from one such dealer...

It guarantees a 1/4 mile time of 11.20 or better! How's that for putting your money where your mouth is!

Today's Z06 is undoubtedly a much better machine. Built to do it all and stay in one piece. Again, however, old Detroit iron will always have a special place - it earned it.

We all must rejoice and hope that the HP wars continue!!!!!!!

If I come across that mag, I'll scan the ad in and post it.

koki345

This Nickey Camaro ran a 13.9 @ 108 MPH - on Casler drag slicks.. A good running, bone stock LS1 C5 Corvette would match that.

The cylinder heads of that era were archaic by modern standards. The big block Chevy's valve angles, for example, were 26 degrees on the intake and 17 degrees on the exhaust. The LS7's are a mere 12 degrees on both intake and exhaust. The differences only begin there. The LS7's heads alone are worth perhaps 100 NET HP over the best stock big block Chevy head.

StickShiftCorvette

First I agree the Z06 is a better car if you can stand a non-convertible sports car.

You could get a ZL-1 with either a convertible top or a T-top.

But you are dead wrong on several of your numbers. First see what times a new Z06 would post on F70-15 bias belted tires. Tires were the largest part of "heavily modded" on those drag cars.

The actual output of a ZL-1 was generally acknowleged to be between 560 and 600 Gross HP or 425 and 500 Net HP. It was not extremely streetable since it had a fairly wild solid lifter cam with a large Holley Carb.

From a purely power perspective, it HAS taken a long time to catch up to 1969.

Some still don't consider non-convertibles sports cars (race cars, GTs) so GM has yet to match '69.... (Not that mine is a ZL-1).

koki345

The "generally acknowledged" output figures are nothing more than urban legend and have no basis in reality.

Here are two actual ZL1 engine dyno results - with known variables. Each of the two engines produced very similar results in comparable test configurations.

[As a baseline, modern day comparison, consider the fact that his little 346 cid LS1 produced 503 Gross HP on 92 octane unleaded with a carburetor (which eliminates the "but it has modern EFI" excuse), open long tubes, LS6 valve springs, a relatively mild (.525" lift) GMPP cam and no other mods]: http://www.superchevy.com/technical/...s/0409sc_gmpp/


Bill Porterfield's ZL1 engine dyno results:

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

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

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

Air cleaner, alternator, AIR
pump removed - 447.2 HP

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

Chambered exhaust system
removed - 523.6 HP

Pete Simpson's ZL1 engine dyno results: (427 GROSS HP - baseline - with no engine accessories, no air cleaner, no water pump, a huge velocity stack and open stock exhaust manifolds):

tomato

I agree the old ZL1 is a dinosaur compared to today's LS7. However, one point is that the old motor is / was very easy and inexpensive to mod. That's what a lot of the COPO dealers were doing to post big numbers. Remember, too, the Nickey was not on the ZL1 platform. It had the old cast iron block and heads.

koki345

The new motors are easy and inexpensive to mod, too. [They're also much lighter (~ 485 pounds including the flywheel).]

Example: 503 documented HP from this little 346 cid LS1 on 92 octane unleaded with a carburetor (which eliminates the "but it has modern EFI" excuse), open long tubes, LS6 valve springs, a relatively mild (.525" lift) GMPP cam and no other mods:

http://www.superchevy.com/technical/...s/0409sc_gmpp/

Corvette ED

The new ZO6 is best Corvette yet. Now that being said, anybody can drive a C4,C5, or a C6 down a good road with all of the great comforts such as air conditioning and power options at 120mph and up.

Now drive a 67,68,69 427/435 Vette with no power steering or power brakes down the road @ 130mph + this separates the men from the boys. The two cars can't be compared because it is different technology.

I can remember driving my 1969 Corvette 427/435 4 speed 3:70 gears at 135 mph and the car is taching like 5 grand and screaming for another gear to shift into. Driving my 2001 Corvette 6 speed at 135 with the air on and the cd playing the car feels like your going 70.

tomato

I agree. That's the beauty about Chevy's. I had a 67 Camaro 327 that I pumped out 455 naturally aspirated HP (flywheel) from...02 Camaro SS with an LS1 putting almost 360 to the wheels as well.

mr-z

The ZL1 produced 376 SAE NET HP as installed in the vehicle. As such, is was a low 13 (and arguably a high twelve) second car.

Yes there were only two ZL1's in 1969 that were released to the public. They were yellow with black designer stripes. The horsepower was underrated and the true HP was way over 500 HP.

tomato

Awesome point! I remember quite a few times in my 68 Chevelle where I thought the front end was going airborne! That baby put 633 HP to the flywheel and my best ET was 10.88. 427 with solid lifter cam and huge lift/duration. Ran on 115 octane and scared the living $^% out of everyone that ever got in it with me (including me).

DDSLT5

This is SO true. A buddy of mine recently put an LS7 into a 67 vette. It keeps all the interior and exterior cues, with some bigger tires all around and C4 grand sport brakes. It feels just like my bro's 67 big block. It sounds awesome, and when you drive it, it is an EXPERIENCE! This thing has power steering and brakes, but the clutch is mechanical now (and feels awesome!) and there is a little bit of slop in the steering. You floor it, the whole front end points to the sky, it kinda roams around the lane as it smokes the tires! You feel like you're trying to wrestle an elephant! It is just CRAZY fun!!!! It feels like you've got 1000 hp under the hood, yet it is a stock LS7! Driving that car over 100 mph takes BIG *****! Cruising in my ZR-1 or C5 at 180 mph feels WAY smoother and under control.

If you guys ever get a chance to ride in a 67 with an LS7, don't pass it up! Modern big block performance and old school feel - nothing like it!

waynet

There were only 2 ZL-1 Corvettes ever built and Roger Judski owns the Yellow one (a coupe), which is in the video that I will mention later. There were only 69 Camaro's produced with this option.
I personally interviewed Bill "Grumpy" Jenkins in a segment for "The Ultimate Bow-Tie Muscle Car" Video and he related that an iron block 427 with aluminium heads, almost always made More HP than the ZL-1. The reason : The aluminium block would shift and not make a perfect seal. In other words excessive leak down, which translates to HP loss.
I am not saying that the ZL-1 was a mutt, but it was not as dominating as everyone thinks it was! I also agree that a stock Z-06 would kill a stock ZL-1. Just my 2 cents

vettemaster1

you nailed it on the head.....any vette before the c4s was down right scary over 100.....

while i will always love all corvettes, i will never own anything other than the lastest generation....the newest is always the greatest!!

koki345

I'd argue that the newest wasn't always the greatest, at least in terms of engine output from '71 through perhaps '84.

Low octane, unleaded gas and ever stricter emissions standards killed performance. Newer crash standards added a lot of weight, beginning in '73.

Each new model year promised a slower, heavier, poorer running car.

Corvette (and Camaro) performance really began to turn around in '85 with the advent of the TPI L98 and took a big leap forward with the LT1 (300 SAE NET HP) in '92. It's been all up hill since, with the LS1 ushering in the modern era in '97.

The switch from Gross to Net power and torque ratings in '72 mislead a lot of people into believing that power losses were far more significant than they actually were. That belief still continues to this day with many.

In real terms, a bone stock '92 LT1 Corvette was a full match for any older 'Vette, with the possible exception of the L-88 and ZL1, each of which was was quite rare (and totally devoid and any comfort/luxury item).

gofastvette

But not necessarily the fastest. Downplaying the L88, ZL1, and 454 LS7 only indicates to me your lack of driving time behind any one of them. I will admit some late models are quick, But I personally ran 11.4`s in 1969 and drove the Vette back and forth to the strip.

koki345

No Corvette that was remotely stock ran 11.4s in 1969.

Heavily modified Super Stock Chevys (e.g. Bill "Grumpy" Jenkin's SS/B big block Camaro) with over-bored engines fitted with unrestricted after-market cams, 3 angle valve jobs, aftermarket intakes/carbs, milled heads/decked blocks (fully blueprinted to NHRA tech bulletins), super-tuned and running open long tube headers, massive slicks and 4.88 gears weren't that fast in 1969. That's historical NHRA fact.

Here's what an 11.55 second, NHRA SS legal, big block Chevy looked like in 1969:

http://www.quartermilestones.com/pho...n2/RMA6902.jpg

This recently tested "435 HP" 427 'Vette, fitted with the optional L89 aluminum heads, managed a 13.8 @ 105 MPH, which CAR AND DRIVER correctly refers to as, "fast times for a 1968 car." The full throttle 60 MPH to 100 MPH segment of the standing start acceleration run required 7.6 seconds. None of those times are remotely indicative of a low 11 second car.

http://www.caranddriver.com/comparis...-corvette.html

Exterminator

Thank you, nuff said.

GN1270

So where are the ZL1 cars trapping anywhwere near 129mph? Even with those tires the trap speeds should be much higher than 105. Top speed is listed at 130.

LTC Z06

As far as 1/4 mile goes, let's not forget braking, hadling, gas mileage, and creature comforts.