ChrisUlrich

3.08s or 3.23s? Car is a 383 with twin t60s.

Currently the car has a Moser 12 bolt with an eaton carrier and 4.11s. So I am thinking the 4.11s gotta go, no?

Anchor

What carrier do you have? If it's a 4 series, tallest you can go is 3.7's.. A lot of supercharged/turbo factory M6 cars here in aus come with 3.7's standard. It's what i've gone with from 4.11's.

If you have a 3 series, i'd lean towards 3.5's. Too high and 6th will be useless unless you're doing some Bonneville passes..

Packy

iTrader: (11)

I would say 3.73's will work for you.

30th t/a

iTrader: (51)

3.42s + 6 speed = perfect for turbo setup. I wouldnt go any higher that 3.42s

ChrisUlrich

Thanks for input everyone! I love the ideas and suggestions!

67Firebird455

iTrader: (27)

I agree... Had 4.10's in my M6 TA and it wouldn't hardly build boost until 3rd gear. The fact that you've got twins and a 383 will definitely help! I'd find out what carrier for sure, then shoot for mid 3 gearing.

got-a-ls1

iTrader: (12)

i loved the 3.23 when i had the ten bolt. with the dana60 i could only go 3.54 and i like that as well. 3.23s would just pull forever though haha

fotoboy

iTrader: (1)

3.42 and a 6 speed is darn near perfect through the traps at mid 140 in fourth.

ChrisUlrich

Mid 140 in 4th? I never do 140 in 4th gear, ever! Although, I did spin to 6000. haha

stevieturbo

A lot will depend on traction available, tyre size, and usage, and of course how much power/torque you're making trying to defeat that traction.

At a guess though, I wouldnt want anything numerically higher than say a 3.5 for a twin turbo setup, which at present with your 4.11 probably smokes the tyres with ease in 1-4 gears, and maybe even 5th.

The Alchemist

iTrader: (19)

I'm not a turbo, but a procharger, and I have 3.73s and will be going back down to a 3.42 as the 3.73s are just too much for 1st and 2nd gear.

Tally TransAm

iTrader: (17)

tire size is a pretty important factor here

stock size and 3.42's is a nice setup. i run 3.70's and 28"s which is close

BOBS99SS

iTrader: (2)

Im sticking with 3.42s,