i have a 97 blazer 4dr. 4x4....can someone tell me what size rear end i have a what would be a safe amount of RWHP this rear end could handle.....looking to replace the 4.3 with a built 350 sm. block

 

You most likely have the 7.5" or 7 5/8" rear. 28 splines. Check your glovebox for RPO G80 which is the limited slip differential. Also look for a GU(#) code, most common being GU6 that is 3.42 gears. You will have to ask some of the V8 swap guys if they did anything special to beef up their rear diffs.

 

Question: (not to steal the thread...but) If your glove box code doesn't list G80...Think mine says G06, can you swap out internals from a limited slip. Are the housings the same size? Maybe I'm looking at the wrong sticker...?

 

G80 is the carrier, (internals as you put it) not the housing so yes you can swap out a non G80 with a G80 but you will have to get the pinion to match the carrier which requires you to set up the entire rear end with backlash and all that nonsense. It is easier to find an entire rear axle with the G80 already installed and swap out rears unless you have the expertise to set up the rear yourself or the finances to pay someone to do it. However, I do not know of any 3.42`s (which is the GU6 you mentioned) that were also limited slips so unless you have 2wd you are also looking at replacing the front differential to match the gearing of the rear. 3.73`s were the most common limited slips in our trucks.

You could also get a drop in locker from Summit but again it is a matter of $$$.

 

Thanks trippleblack. Would this work for a limited slip with the 3.42 gears?

http://store.summitracing.com/partde...4902613+400018