I bought my firebird with the v6 to v8 swap done half way, I finished what the guy started, i got the correct front springs, and corrected his wiring.

but Im putting in a SBC 350 I built, it should make about 380-390 HP at the flywheel.

So im looking into building my rear end to take this. but I know nothing of the rear end, is it a 7.5 or 7.625?

in the tech article it didnt list to much to make the rear end stronger, is it really that simple?

are there any steps I can do and take it a step farther?

 

Somewhere around 85-86 GM upgraded the 7.5" ring gear to 7.625". They both fit on the same carrier so even the newer 7-5/8" diffs are still called 7-1/2" diffs.

No matter how much you beef it up, you still have a tiny ring and pinion. Price out the cost of new 28 spline axles, solid crush sleeve, rear cover with bearing cap supports, the cost to weld the tubes and you could almost buy the bolt in 9" housing with axles. You'll still need a center section with gears and carrier but you'll be getting a stronger diff for only a little more money.

The first 7.5" ring and pinion that you break will eat up the extra costs.

Of course I also ran low 11's on a beefed up 10 bolt. The only reason I switched to a 9" was that I installed a transbrake and knew the tiny gears wouldn't handle the shock of a transbrake launch.

 

Someone said one time that you can strengthen a 10 bolt in the same way that a baby could fight Muhammad Ali.

 

I went 12.50s with a stock rear and a 5 speed. An auto car wont shock the rear as bad so it may last longer. My motto is to not fix it until its broke.