forum.jdrace.com

Hi! I'm new to the site and am also not to up on rear end gears. What I'm looking for is the 3rd member for my 1978 El Camino. I recently put in a new 355 sbc turning about 425-450 hp. My rear gears are 2:73 open 10 bolt. I would like to go to maybe a 3:42 posi rear. Does this sound reasonable. I run it on the street only. I really don't want to change the housing, just the gears.
Thanks in advance!

Yep - very doable...

what you need to understand is that there are different series carrier to hold different ratio ranges.

The 7.5 10 bolt rears are as follows.
2.14, 2.29,2.41, 2.56, 2.73, 2.92, 3.08 are all 2 series gears from GM
3.23, 3.42, 3.73, 4.10, 4.56 are all 3 series gears from GM

Aftermarket gears are available in thick (3 series ratios to fit the 2 series carrier) and regular ratios from 2.73-4.56

So the posi unit can be a 2 or 3 series unit be careful when buying so you get matching parts.

We have posi units and gears and even rebuild kits at discount prices when you buy one at one time.

If you PM me I will price you out a package hopefully that will fit your price range. I just need to know that price range as i already have the info that is will only be a street machine. :0

Thanks, Jim Mitschke