TLS_Addict

I don't understand how you can't spin the tires. From even a slow roll you should light them up with ease.

27" tall tire should not matter. What converter are you running?

Kacyc3

guessing stock and below rpm range.

MelWff

Based information on GM Archive Center PDF page 73 didnt list a 3.08., thanks.

https://www.gmheritagecenter.com/doc...t-Corvette.pdf

redvetracr

according to the Willcox tech site "AW" was a 3:08 available in 73-74-75 but 45 years later why would you assume it`s the factory installed diff? 65-79 aren`t they (pretty much) all the same?

L-46man

My L-46 (which years ago dynoed out at about 380) '69, has 3.70 posi. (M-21 4 speed man,which will light the tires in three gears) I feel that in general use it's too tiring and thirsty with the 3.70. More of a stop-light to stop-light car.

So my vote would be the 3.55

On the other hand, the 82 CE has 2.87 rear with the 3.36 first gear thru the 4 speed slushbox....which Will spin the huge 255/60's, yet is so comfortable and docile on the highway.

Tough choice. so the decision really is....HOW MUCH DOES BURNING RUBBER MEAN TO YOU!

Good luck Unkahal

You might want to think about a different torque converter.

mwm3006

Thanks for all the info. The converter is a 2000 stall.

jackson

GM heritage center states '79 C3 had only one auto trans (TH350) and only one rear gear for all automatics regardless L48/L82 ...

only rear gear 3.55:1 for all automatic trans '79 C3

https://www.gmheritagecenter.com/doc...t-Corvette.pdf

Grumpy 427

I have an 80 vette, 255/60/15 tires all the way around. 355 sbc 340 hp 390 tq, with a reworked stock converter, now flashes to 2200 behind this motor. I had 308 gears in the car, and that was the wrong gear for this combo. I switched to 3.55 gears, and the car now boils the tires when i nail it, and actually drives and accelerates away from the traffic lights etc the way it should. It just drives all round better. I gained 500 rpm with the gear swap. so now 100 mph is 4500 used to be 4000 rpm.

Rotonda

Agreed, there was no 3.05 ratio, BUT there WAS a 3.08 ratio which was used extensively in the later rubber bumper C3's, especially automatics. Rather than changing the ratio, put in a 700R4. The lower 1st gear ratio will give you everything you need and give you quiet cruising as well.

Gunfighter13

For what you say you are using the car for I would recommend you have the 12 bolt mod done with 3.55 or 3.73 gears. That way you will not need to upgrade later on. Do it right the first time.

Krystal

I'm running a 383 with 3.08s and and an auto shift.

Seems like a good combo to me. In my case demolishing tires from a standing start on street tires is effortless through all of 1rst gear and a pretty healthy "bark" of the tires happens as 2nd comes up that is likely due to the shift firmness of a TCI Super Street Fighter Turbo 350 trans. Mean-while RPM, at highway cursing speeds, is quite reasonable considering there is no "over-drive" in this transmission.

If you aren't finding this to be the case......makes me wonder about how healthy that engine is.

Higher gear ratios might give you a little more "go", if you can find traction, but you'd really need that 4 speed auto to keep anything close to a reasonable RPM out on the highway.