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Re: 1969 white coupe ZL-1 on BAT
OMG! Another one comes out of the wood work or garage.......
Big Tanks In the High Mountains of New Mexico -
Re: 1969 white coupe ZL-1 on BAT
This one doesn't appear to be one the the two originals that GM assembled at St. Louis.
I have a recollection that one of the real St.Louis-built ZL-1s was confiscated by Feds as part of a drug bust, and I recall that it ended up being auctioned off... sometime back in the nineties?
Does anyone else have such a recollection?
DukeComment
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Re: 1969 white coupe ZL-1 on BAT
Duke -this info has been covered a few times previously on the TDB.
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Re: 1969 white coupe ZL-1 on BAT
Question: "Why did the ZL-1 that was dyno tested produce less horsepower (523 hp) than an L-88 (over 550 hp)?"
Thanks in advance for your response.
Rob
SPEAK YOUR MIND, but ride a fast horse. -- AnonymousComment
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Re: 1969 white coupe ZL-1 on BAT
The ad listing says it all:
ZL1- POWERED 1969 Chevrolet Corvette Cpe.
E.J.Comment
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Re: 1969 white coupe ZL-1 on BAT
People are constantly throwing horsepower numbers around without providing full context. Full context requires, first, whether it's a lab dyno or chassis dyno test including the make/model of the dyno. The type of correction factor used, if any, must also be stated. Then details of the engine's configuration must be provided, especially the exhaust system.
Back in the day press reports stated Chevrolet claimed their own tests of L-88 with headers and open exhaust yielded about 560 HP at 6500 on a lab dyno with STP correction, and I believe that this was a hand build race prepared engine with true 12.5:1 compression and likely race massaged heads. An equivalently prepared L-72 with a true 11:1 CR, massaged heads and racing exhaust system will make about 500 HP.
An equivalently prepared ZL-1 will make about the same power as a L-88. The aluminum block doesn't add power. I just reduces L-88 weight by 100 pounds or so. The ZL-1 weighs about the same as a cast iron block/heads small block, about 150 pounds lighter than a production cast iron big block.
The Web page states that a previous owner had the engine tested and it made 523 HP with all stock Chevrolet parts. Chevrolet sold a complete big block racing exhaust system OTC. Was that stock? Was this engine hand built with all typical racing prep. Optimized CR? Massaged heads?
My guess is that this engine was not fully race prepped - CR not optimized and no head massaging, but was tested with headers and open exhaust, on a lab dyno with STP correction.
In the car with OE manifolds and that extremely high overlap racing cam designed specifically for headers and open exhaust it would not even come close to 400 SAE corrected RWHP, which is less that what a current showroom stock Sting Ray's LT2 will show on a chassis dyno. In addition the L-88 or ZL-1 barely idles at 1500, is difficult to get going from a dead stop, will overheat rapidly in traffic... definitely not a pleasant experience in normal real world driving.
Always view claimed horsepower ratings with a grain of salt unless full context is provided.
Duke
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Re: 1969 white coupe ZL-1 on BAT
Duke--
Wow!! Thank you so very much for taking the time to prepare a detailed response to my question!!
Not being an engineer, or mechanic, I could not understand how a ZL-1 engine with "equivalent Chevrolet components" would produce at least a 5% decrease in horsepower from a similarly equipped/configured L-88 engine. Now after reading your outstanding explanation of the many variables associated with the ZL-1 versus L-88 comparison, (to include dyno testing factors), I have a much better understanding of why this occurred. Suffice it to say, your answer was exactly what I hoped for; and I truly appreciate your kindness in taking the effort to "educate an old dog!"
Again, thank you very much!Rob
SPEAK YOUR MIND, but ride a fast horse. -- AnonymousComment
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Re: 1969 white coupe ZL-1 on BAT
Right. The ad copy never says it's a ZL-1 car with its original engine, or even that it's a ZL-1 car with a replacement engine...
The car is crusty and cracked around the edges but if the engine runs, that alone may be worth the current bid of $30k.Mark Edmondson
Dallas, Texas
Texas Chapter
1970 Coupe, Donnybrooke Green, Light Saddle LS5 M20 A31 C60 G81 N37 N40 UA6 U79
1993 Coupe, 40th Anniversary, 6-speed, PEG 1, FX3, CD, Bronze TopComment
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Re: 1969 white coupe ZL-1 on BAT
Ed,
You and I both commented on this car on the forum a while back as well as a long thread on the ZL1 cars. It would be a fun car to own but it definitely left St. Louis as an L71 M40 car. GM records show 2 RPO ZL1 cars built. The yellow one owned by Roger is one of the 2 and the other one is unaccounted for in my opinion. The white car from the Otis Chandler collection is too early and most likely left the factory as an L88 and raced with a ZL1 engine. The orange M40 convertible was built too early and there are a lot of question marks around this car in my opinion. The car does not have the original motor and there is no verified paperwork linking the vin of the car to having the RPO ZL1 option. In addition it has two different dealer order forms presented with the car over the years with different engine stamp numbers. Like I said the second one is still unaccounted for but unfortunately this white car on BAT isn't the second one.Comment
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Re: 1969 white coupe ZL-1 on BAT
Duke,
Here is a little history on the yellow car
Tallahassee_Democrat_Sun__Oct_13__1991_zl1.jpg
69 zl1 dea.jpg
ZL1_shipper.jpg
hechler zl1 invoice.jpg
ad zl1.jpg
Yellow Zl1.jpgComment
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Re: 1969 white coupe ZL-1 on BAT
Duke,
Here is the yellow ZL1 next to my unrestored red red 69 L89 at a show in Boston. Kevin C the previous owner of my car had Zora sign the original paperwork at that show:
Red and the ZL1.jpg
69 zl1.jpgComment
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Re: 1969 white coupe ZL-1 on BAT
Auction just ended... $105K, sold. I wonder if magnumrzr was a shill bidder just trying to bump the price.
DukeComment
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