Joe D.430

Hi all,

I am going to be putting a LS3 motor in my 1982 corvette soon, and I am just trying to figure out what the best automatic transmission and rear end ratio would be for that motor in that car... Any suggestions?

Thanks,
Joe

Jimbo1367

What are your plans for the car? If I was wanting a stick, I'd go T56 6-speed. Something like this www.summitracing.com/parts/CMG-TUET11012/ or just sourse one from a 4th gen F-body. You won't get the deeper 1st gearing though. (2.97 vs stock of 2.66) If a auto is your preference, then a 4L60E (60/65/70).

garys 68

iTrader: (1)

The aluminum 82 vette diff housing only came in 2.8-2.7 something ratios. They were also not very strong. I would suggest checking what ratios ring/pinion gears are available for an 82. I'm guessing you wont find much.
If you're stuck with that stock rear end, it might be hard finding an auto OD trans that wont put you under a 1.9 overall ratio. Other than that the TH400 in your car would work.
For a manual, the Richmond 6 speed comes in a variety of 6th gear ratios and the TKO 600 5 speed is available with a 0.8 OD.

Joe D.430

Jimbo - The plan is for it to be just a street car, probably will leave the LS3 stock after it goes in. The 4L60E looks good, also the guy at Turnkey suggested the 4L65E. My father and I are working on this project, I like stick better but it is his car and he likes auto so I am thinkin auto it is ha... Gary you suggest the TH400 do you believe that is a better trans? Looks like from what I see on summit the TH400 is by ATI and the 4L60E is B&M? Looks like the 4L60E is a bit more pricey but if it is better quality I think we rather have that. About the rear end, we figured the stocker was definitely too weak, so we plan on replacing with a nice 12 bolt of some sort. There shouldn't be any problem making a 12 bolt work should there? Just not sure what kind of ratios would be good for a solid low end but still a decent highway gear... maybe 3.73:1?

Thanks for the responses guys
-Joe

garys 68

iTrader: (1)

A 12 bolt is possible on ealier (uo to 79), but I'm not sure if the later ones can be easily converted. Look up Toms differentials for corvettes.
The TH400 is really tough, but the main reason I suggested it is because I'm thinking you may be stuck with the stock diff and an OD trans with a 2.73 rear is probably going to be too much gear.