[Al'z56]

I'm building a 56 Chevy truck and looking to get some opinions on which rearend to run. So far Im thinking between the 12 bolt car/ truck or the 9 inch.
My truck will be used mostly on the street but will see "some" track time. I think I will have to narrow any rearend i get cause I need somewhere around 55.5" to 56" from mounting point to mounting point. My engine is a 454 that puts out 600lb/ft @ 4300rpm and 570hp @ 5600rpm @ the crank. Trans is a T-400 and my stall will be around 2500- 3500? "not sure on the stall yet" Any help will be greatly appreciated.

Thanks,
Alex

[tjet]

Don't forget the Dana 60. I have one in my '58 pickup. We need to "spread" the springs out a little to make it fit

[56GM]

I've got a GM 12 bolt truck underneath my project 56 GMC, works fine its on a 72 c10 frame. I don't think it'll make a difference.

[big gear head]

I've got some 9 inch Ford rear ends out of '59 Fords that are about 58 inches wide over all. What is the total width that you need?

[Al'z56]

Its looking like i'm going to need about 55.5" to 56" over all width. I'm running a 20x10" rim with a 3" reverse backspacing and want them to tuck inside the fender. I'm trying to find a rearend that will hang with my motor and the best bang for my buck... If between the car/ truck 12 bolt and 9 inch is going to cost around the same to rebuild "narrow, new axles, posi, and gears" which would be best??

[ogre]

there is a lot of 55-59 chevy axle swap info in the 55-59 chevy truck thread. i posted a couple of links there for axle swap info. i personaly have an 89 trans am rear end under my 58. 66'' wide with disc brakes. most any axle you mount under there will need the spring perches welded on in the right spot.

[cobalt327]

I may be mistaken, but to swap the truck rear end for a 7.625" 3rd. gen F-body rear end is a move sideways at best, strength-wise. Behind a BBC making 600 ft/lbs., well...

If the cost is equal, I'd use a Ford 9" if for no other reason that changing pumpkins (and ratios) is so easy. The strength wouldn't be an issue, either.

There may be a truck rear end housing that would need little more than the original perches removed and the Chevy perches rewelded onto it, w/o the need for narrowing, w/luck.

Knowing the axle flange to flange width would help.

[big gear head]

The only reasonably strong rear end that I know of that is narrow enough would be a late S10 2 wheel drive 4.3 5 speed rear end. These trucks got the 8.5 10 bolt with 30 spline axles. I would change the Governor Lock for an Eaton Posi, but otherwise it would be good.

[bighotroddin]

Thats alot of power maybe you would be better off with a aftermarket 9" built to the spects of the truck.