I want to add a Limited Slip Diff and 3.42 gears to my car. I have a '91 Firebird w/ L03 and T5 tranny. I found this package on Ebay:
eBay Motors: Eaton Posi Package GM 7.5 10 Bolt w Gears and Mstr Kit (item 280002302970 end time Nov-24-06 10:29:32 PST)
It comes with Motive Gears, Eaton Posi, and a Master Bearing kit. I can alkso get each component separately for a little less at different ebay stores.

I'm probably going to get this done at a shop and I have a few questions:
1. What do you think of this package?
2. Is the master bearing kit the one I would need and is that a good one?
3. Are Motive Gears good?

 

the only thing i don't like about that kit is the OEM crush sleeves...get a solid pinion spacer to replace the crush sleeves and you'll be good. Motive gears are among the better gears out there, they seem to run "quieter" than others and are strong gears.

 

OK, where would I get a solid pinion spacer?

 

Look down this page about 5 or 10 posts to one about building a 10-bolt. The Ratech part # is in there. Just about any place that carries Ratech - Summit, Jeg's, your local speed shop or gear place, various board sponsrs, etc. will have it.

 

What is a reasonable price to install this package in my car?
Also what do I need to change my speedometer to correct for the new gears?

 

Motive are good quality gears and you can't go wrong with an Eaton posi. If you wanted to get the best quality bearing set available, Timken is the way to go. Koyo's are offered in most kits, but "premium" kits come with Timken bearings. If you want to get a solid pinion spacer, there's another ebay seller that has them available for the 7.5" ten bolt. Search for ebay member 'lotsoffun77". They're about $18 from him IIRC. If you're going to have a shop do the work, plan on roughly $200-$300 in labor for them to set it up for you. IIRC you'll need a 7 tooth drive gear and a 21 tooth driven gear for your speedo to read correctly with 3.73's and a T5.

 

yea, ratech is the only company who makes the solid spacer for the 10 bolt, that I know of. This ebay seller might be able to toss one in the kit, if you're spending $600...
If you just drove up to the shop and told them "install this" and handed them the box, and came back the next day, i'd think you'd be out around $800.

 

Randy's Ring and Pinion helped me out with gears and the solid spacer.
Randy's Ring & Pinion - Your Source for Differential Parts