How much horsepower can this rear end take? Is it worth keeping if I wanted to do a LS conversion?

 

Well, considering that the LS1 cars themselves came with 10-bolts; and that rear is marginally stronger than a 10-bolt; I'd say, depending on its condition, it should hold up about the same or slightly better than a stock LS1 rear.

Kind of a terrible gear to put behind a motor that likes to rev.

If it has the crappy cast-iron brakes, I'd suggest looking for a LS1 10-bolt, in preference to spending the money to put gears in that one.

If all you're looking to do is just run it because you've got it, then it doesn't too much matter what "it can take"; you're going to do it anyway, and it'll take what it'll take, or not, and that'll be the end of that.

Should be OK at least for awhile as long as you don't get a lot of traction, (no slicks) and keep it out of wheel hop (add LCARBs).

 

Thanks for the info! I was told the gear code in my car GU5 is a 3.27. I'm new at all this stuff with the 3rd Gen Fbodies. So I need all the help I can get.

 

I'd avoid the "codes" and spend more effort finding out what's ACTUALLY in it.

Seems like about 75% of the time, when somebody buys parts based on the "codes", it turns out that they're wrong, because somebody has changed something somewhere along the way.

Go catch up on some of your "deferred maintenance" and change the rear end fluid. While you're at it, inspect the parts and see what they are. MUCH more reliable than a bunch of "codes".

Considering the LS1 cars came STOCK with more gear than 3.27, and everybody always seems to want more than what they DID come with, I'd be inclined to suspect that you'll find 3.27 isn't enough.

 

The 9 bolts were put in the 350 and tpi cars as the upgrade rear over the basic 10 bolt and are supposed to hold 400hp or a little more. They are a better designed rear than the 10 bolt. If you break an axle they won't fall out like a 10 bolt since they are bolted in at the backing plate. The posi works better and last longer also. They are a 7.75 inch rear and the 10 bolt is 7.50 making the 9 bolt ring gear bigger and stronger. They were more expensive than a 10 bolt and made in Australia so GM went all 10 bolt in 1990. All of my 3rd gens have a 9 bolt with PBR rear disc except one and it has a ford 9" with C5 vette rear disc. You can get 3.45, 3.70 and even 4.10 gears for a 9 bolt and posi units and cones and most parts to rebuild them.