can soemone tell me all i need to know about my rear. so far i know its a 2.73 open diff and i want to put some 3.42's in it and posi but don't know the size of the rear besides it being a 10 bolt

 

7.5 / 7.625 is what you have. Different numbers same rear.

 

with 2.73's you have a 2-series carrier. You can buy gears specifically designed for that carrier (ring gear will be thicker), but if you are planning to upgrade to a posi, just get 3-series gears since you'll be changing the carrier anyway.

You may have issues with the axles. 89 is a shady year. Somewhere in there GM switched from 26 to 28 splines but I am not sure where. Most aftermarket posi units are 28 spline (someone else was looking for 26 spline, but I don't recall if he ever found them or not). If you really want new guts, might as well get Moser axles. They are way stronger than OEM.

How much are you looking to spend on this thing. It might be easier to find a different rear end than trying to change everything out on this one. Plus then you can get disk brakes (don't know what you have on there now)

 

it really depends if i could fine a good disc rear with posi and gears i;d spend around 500 if it has everything.

 

Eaton posi unit+timkin installation kit+Motive Gears = $600
LSI 7.65 rearend cover (girdled) - $130
Moser axles w/ studs- $270
Total (all prices include shipping) $1000

Now i just gotta install it all

BTW, those are all 26 spline

 

come to think if it, I think it was Rabbitts post asking about the splines.

So if you are replacing everything, why did you stick with 26 splines? Might have as well gotten 28, they are supposed to be a little stronger.

And where are axle bearings/seals and solid spacer? That would be another $50. I also found setup pinion bearings from precision gear to be invaluable. Those are another $50 + ship. You might also want to get more of the gear marking compound before you start.

Problem with 10-bolt is that another ~$200 for the rear itself + the labor (of unknown quality) if you don't do gears yourself and you are getting dangerously close to the cost of a very decent 12-bolt.

 

i asked myself the same question after i got the parts.. trust me.. and I started with the rear.. i forgot about the outter axle bearings... and thats all the money I had set aside for it.. hehe. And i know plenty of pple that can do the rear for me (pros) so im not worried about the quality. The best rearend price i could find ina 12 bolt was around $1600. And, with a little welding for structure, my current rearend (after rebuild) should be able to hold up to around 400 RWHP (info via Chevy Hi performance or Super Chevy.. one of the two). Sooo.. i would need roughly around 472Hp at the crank (If i lose about 18 percent of my Hp through the drivetrain). I dont plan on having that much power, so, to me, the extra $600 could definately be spent elsewhere..

(sorry about the really bad grammer.. lol)

EDIT:: Oh yeah, labor is gonna cost me a case of Miller Light

 

I am doing the same thing with my car. Started with the rear, then found the LS1 driveshaft and now just finished rebuilding the tranny. Engine will be the last thing to be put into the car. Yeah, that's why I said if you have someone else do it.

But while you have the entire thing open, I would definitely get axle bearings and more importantly solid spacer ($17). Last thing you want is to invest all this time and money just to find that bearing goes bad or seal starts leaking 2000 miles after you start driving. And it is a $20 dollar part that you can buy now and install in under 15 minutes.

 

will do! im not doing the rear for awhile anyway.. the guys who can do it for me are too busy

Thanx