Pure Stock Muscle Car Drag Race

[JoeC]

I misread the '69 Camaro order form. You are right Stan. There appears to be four selections under the "AXLE, REAR" heading. RPO's G80, ZQ8, ZQ9 and the fourth box is the blank space to write in a ratio. Then the power team chart has four columes Std, Econ, Perf, and Spec. My question is if you could have writen in "4:11" on the Corvette order blank for a TH400 L71/L89 or L88 or ZL1 would it be factory installed or dealer installed? I do not have a power team chart for the 1969 Corvette. The 1969 Camaro Power Team Chart goes up to 4:10 and the '68 and '67 goes up to 4:88. One book lists a 1969 Camaro COPO #9511 code DT 4:56 rear.
Maybe the '68 Chevelle Charley had was ordered by writing in the ratio. Yes Charley that 68 Chevelle would have been a "Contenddaa"

[Rowdy Rat]

Joe,

I'm sure that any available ratio could have been written in, but I doubt that it would have done any good without some sort of central office override. The Corvette power team chart shows a 3.36 rear as the only "performance" ratio available with the L-71/L-89/L-88 and M-40, with no "special" ratios available. For whatever reason, the engineers decided that the most aggressive rear axle ratio a person could get in a Corvette with an automatic and one of the the solid lifter engines was a 3.36. They even created a special broadcast code (AX) for this application even though a "big block" 3.36 rear already existed (although to my knowledge, there is no physical difference between the two). What I was never able to understand is why the higher numerical ratios were never offered. The COPO Camaros and Chevelles could get a 4.10 (maybe even a 4.56) as you stated. Plus, there was no doubt that the L-88/M-40 cars were built solely to make that combination legal for stock class drag racing, so why saddle the car with a rear gear totally unsuitable for its intended purpose.

For general information, the transmission used is nearly identical to the COPO Camaro/Chevelle/Nova THM400s although the Corvette version carried a "CY" broadcast code.

I've been fortunate to see quite a few of these automatic transmission L-71/L-89/L-88 Corvettes in person and with only one exception, the cars all had the 3.36 rear (the one car that did not was an L-89 with a 3.08). I've heard recently of an L-89/M-40 car with a 3.70 rear axle (supposedly with paperwork), but I have not seen any documentation to this point. If I ever get to see the car and the paperwork, I'll let you know what I discover.

Charley, that Chevelle, sounds like a great combination! It also sounds like you've had (and still have) some really outstanding cars!

Regards,

Stan

[Charley Lillard]

The Chevelle was Grotto Blue with Parchment bucket interior, manual steering, guages, no colsole. It even showed Simulated Mag Wheel covers on the Window Sticker. It went to Dave Simpsom in St. Charles Ill. Most of his collection was bought by Mecum auctions about a year ago then resold. The current owner only has a copy of the Window sticker. Simpson either lost or kept the orig. one. What a shame.

[sixtiesmuscle]

Re: the availability of taller gears in L71, etc. vettes, could the engineers have been afraid of the massive torque ripping the axles apart? My experience has been that the Corvette rear end wouldn't stand up to the same stresses that a 12 bolt will. It could have been strictly a warranty issue. For instance, Pontiac wouldn't offer a solid lifter car for street use,i.e., with a warranty, if my memory serves me. This was because they didn't want the added liability .

[JoeC]

The only reason I can think of that they offered no higher then 3:36 ratio is because of potential TH400 trans oil temp. problems. There was some problems with overheating with the 68 Corvette big blocks and some changes were made in 1969 but engineering may have felt the increased trans RPM with a 4:11 ratio would have caused high temps. in the trans oil cooler thus in the radiator. While the Corvette slanted radiator was good for bouncing a radar signal, it may not have worked as well as the Camaro/Chevelle set-up that did use the TH400 with the 4:10 ratio. Just guessing here.

[bowtie3168]

I wanted to contribute to this conversation, I feel that this is a important topic. When I went to the reunion, Ray Morrison and I discussed "The Pure Stock Drags". Let me start out by saying that I think that the idea of the race is GREAT! There are not many opportunities such as this for everyone to get together and race like this. The people who put on the event should be commended for their effort.On the topic of "clone" cars, I feel that they do belong as long as they are true clone cars. What I mean is, the clones should have proper documentation and display proof of their existence. I think that "clone cars" can be good in the way that if you were to wreck a clone you would not be destoying a piece of valuable history. To the best of my knowledge no Chevrolet "factory" drag racer had a L89 Nova. Dick Harrell, Bill "Grumpy" Jenkins, Malcolm Durham, none of them raced a aluminum headed Nova. Don't you think that they would have raced them if they were produced by Chevrolet Motor Division? I know that the claim is that there were only a handful built and that NHRA and AHRA have minimum numbers that are required to meet to qualify (Chevrolet have to produce 50 L78 Turbo-Hydro cars to meet this requirement for example). I feel that you should be able to build a clone car if you can produce the real car or crediable paper work that everyone agrees with. As for the 1968-1969 L89 question, I have two friends who both own L89 optioned cars, one has a 1969 SS396 Camaro, and the other is (I believe) a 1968 Corvette that also happens to be a tri-power car. Both cars are original (if you can believe it)! So I think that the owners argument could be that 68-69 were both "aluminum head years". I feel that the person builds a clone car should have to prove (beyond a reasonable doubt) that the car was made. Grey area should be addressed properly. There should be no question about a cars existance, if there is the car should not run. I would also like to say that this problem should not keep anyone from participating in the event! If you have a problem you owe it to everyone to correct it!

Thanks,
Andrew

[Kurt S]

Bowtie3168,
There is now a registry for the 69 L89 Camaros. I can dig out the contact info for the keepers of it. I'd also be interested in some info on the car and I could forward the data on. [email protected] CRG

Thanks.
Kurt