Steve Falconi

Hi just wondering if a third gen firebird 410 gear in. 7.5 diff fit on 4 th gen trans am ram air ?? And how much will I rev more at a 100km with a Manuel 6 speed thanks in advance

GeneralDisorder

iTrader: (1)

Third gen Trans Am circa 1987 would not come with 4.10 gearing. So we have no idea what's in that car. 3.42 was the lowest ratio given to any third gen of that era. It is also possible - nay - in fact probable that an 87 Trans Am might have a Borg Warner 9 bolt. Which is entirely incompatible with the GM 10 bolt. Without pictures and verification of gearing - I wouldn't believe any claims of an 87 with 4.10's. Generally Trans Am's of that vintage had 2.77 or possibly low 3.xx gearing.

Also 10 bolt gear sets are CHEAP. Crazy cheap. And new gears will be much easier to setup than used ones. It would be my recommendation that:

A. Buy a new gear set and set it up properly.

AND

B. You don't need 4.10 gears with how much power an LS1 / T56 car makes. You will just be a smoke show.

GD

Steve Falconi

The 410 gears were put in later to replace. The 342 and I’m buying the 410 gears to put in my 2000 was wondering if it would fit since their both 7.5 inch diffs

GeneralDisorder

iTrader: (1)

It should if they are both 10 bolt diffs.

But 10 bolt gear sets are cheap, and it's not worth setting up a used set - which can be difficult and the results (noise, lifespan) may not be worth the added frustration.

GD

GeneralDisorder

iTrader: (1)

https://www.summitracing.com/parts/sum-741015/overview/

$144.

Why bother with used(up).

GD

sofakingdom

iTrader: (1)

^^ This ^^

Or even, not (up).

If you move gears over, you'll have to buy bearings, shims, fluid, seals, crush sleeve or solid spacer, and whatever all else. All of that will cost more than a set of NEW gears. Why waste all that time money effort and RISK on some kinda crap you can order and have sitting on your porch all brand spanking new and ready to TRUST? AND, destroy a WHOLE useful rear that you could sell AS IS and maybe make the whole project REVENUE POSITIVE?

Use the big head to thimk this through instead of the little one.