Looking to buy a posi around the 3.53 area, anyone know a good place to buy or live around Washington area to sell one? This car is running a v6 rear end with a v8. Dangerous and don't feel to comfortable driving it until I have proper rear end for the engine. Any help would be greatly appreciated.

 

I've never heard of a strength difference or there being a V6 or V8 rear other than usual ratios.

 

The '87 2.8 should be a 3.42:1, 7.625", 26-spline. Should be plenty strong for your carb'd 305. Same thing but 3.23:1, then 3.73:1, survived the 350 I swapped into my old '86 IROC-Z. Including trips to the dragstrip.
As for the posi, start checking the salvage yards, or order a new Lock-Right conversion locker.
There are no 3.53:1 gears for the 7.625" axle. 3.42:1 or 3.73:1 are the 2 closest choices.

 

Here are 3.55 gears if you're deadset on that ratio:
http://www.daymotorsports.com/produc...6_PINION_GEARS
You'd need to acquire a limited slip carrier for 3.23 and higher ratio gears of course.

V6 and V8 had basically the same rear other than ratio.

 

WOW! Okay, I stand corrected, and happily!

 

Thank you so much for the input, this definitely sheds some light on the situation. And no im no 'dead set' on 3.53 just something out of the rediculous gears from the 2.8 it used to have.

 

If you had a 2.8 V6, that 10-bolt had 3:42 gears . These are not a ridiculous gear ratio as you claim, except for being a open rear. A limited slip 3-series carrier would work if you can find one that uses 26 spline axle shafts.