Differential swap?
Thread Starter
Heel & Toe
Joined: Apr 2013
Posts: 20
Likes: 0
From: Minnesota
Differential swap?
I have a 1978 corvette and I want to change up the rear differential i hopes of being quicker off the line? I found a rebuilt one and it is off of a 63-early 70's corvette that had a BBC. Will this make any difference in my 78'? and if so, can i just "bolt it on" without any other mods? thanks for the help!!!
Burning Brakes
Joined: Apr 2007
Posts: 1,039
Likes: 62
From: Kona Hawaii
Swap in an OD trans,best of both. 1st gear for start off's and OD for cruising on the hiway.Pick a trans that will complement your current rear gear for a 10:1 overall 1st gear.Example my rear gear is 3.08 times my 3.28 Richmond 1st gear gives a 10.1 overall start off ratio which is considered ideal.My .76 OD 6th gear gives me great mileage on the hiway.Makes for fun driving! Best upgrade on the vette for sure.
Last edited by iokepakai; Apr 18, 2013 at 04:30 PM.
Thread Starter
Heel & Toe
Joined: Apr 2013
Posts: 20
Likes: 0
From: Minnesota
Stamped AWW 2 70 E 1. which is a 3.08:1 Eaton positraction. Rear cover and threaded holes are in good condition. Housing denotes that it is a heavy duty rear differential out of a big block car.
and my car also has the 3.08:1, I just want to know if i will notice a difference with a rebuilt one? or what would you recommend for a rear end? I am putting in a rebuilt 350 and a rebuilt trans. I am new to this so sorry for the lack of info and knowledge on my part!
Race Director
Joined: May 2006
Posts: 18,734
Likes: 2,582
It's the exact same ratio so makes no difference at all. The ratio that would be a perfect middle between performance and economy would be a 3:55. As the other post suggested you can go to a OD transmission as an alternative. At the very least pump out the old fluid put in a bottle of additive and refill.
Racer
Joined: Feb 2013
Posts: 386
Likes: 3
From: Clifton Virginia
I have a 1978 corvette and I want to change up the rear differential i hopes of being quicker off the line? I found a rebuilt one and it is off of a 63-early 70's corvette that had a BBC. Will this make any difference in my 78'? and if so, can i just "bolt it on" without any other mods? thanks for the help!!!
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Pro
Joined: Sep 2012
Posts: 600
Likes: 6
From: Key West Florida
and if you do swap in a 700R4 for the OD, its a very ease swap, need only a shorter drive shaft, shifter if you want to take advantage of holding 1st gear, and a lock up kit, painless wireing sells one, i got mine off jegs when i put a 700r4 in another car of mine, nice kit. very plug and play