I am doing a swap on my stock 10 bolt 88 IROC rear. I bought 3.42 gears but don't know what I will need to swap the old 2.77 out and the 3.42's in. Has anyone done this swap? I have heard I might need somthing called a spacer but I don't know what a spacer is nor where i could buy one. All help is appreciated thanks guys!

 

well where did you get the gears? are they for the 2.73 or? carrier if so then you will NOT need a spacer but, shims you will need unless you are REAL lucky and every thing just lines right up.

without getting really in depth the ring gear should mount to your carrier and will not have to be moved. the pinion has shims that adjust pinion depth. this is more or less a fine tune to get the right wear patter.(where the teeth ride on the ring gear)

 

The gears are Richmond high performance gears. I bought them from e-bay and got them at a great price. they came in the original box although they had been installed once before and run for a week or so. (not raced) I guess if I don't know if they lighn right up I will go to a shop. Let me know if this makes sense. thanks guys peace

 

You have to make sure that they are installed, per richmonds directions. Or you will have a severe wine/howl. Make sure the pinion it set to their specs.[on the end of the pinion] you will need a set up kit. You need a depth gauge and a dial indicator, to set them up properly. I just pulled out a set of richmond 373s that were setup wrong.

 

How ya'll doin, I've been refering to this site for the past month while I get my project car "up to speed"-this place is incredible!!
Any way for the gear swap I had a drum brake 10 bolt with the 2.79 gear in the car. A guy in town parts out 3rd gens so I bought a 10 bolt drum brake rear with a posi unit and 3.08 gear and another 10 bolt no posi 3.42 gear and disc brake. I took the posi out of the 2 series carrier and installed into the 3 series rear. Unless you purchased the thicker gear set you will need a spacer between your ring gear and carrier. 2 series carriers cut off at 3.08, then the 3 series carrier starts at 3.23 and higher (numerically) the difference is ring gear thickness, 2 series rings are approx. 1/4" thinner than a 3 series ring. I called jegs and he didn't know anyone that made a spacer for the 7.5 rear ends, so I got online and found a place in Arizona that make them $67.00 shipped to my door. Changing everything over was another story(I've got murphy's law for a curse) but otherwise it was very straight foward. Anyway if anybody needs the name of the place for the spacer throw up a post and let me know. I'm just glad I know alot of people otherwise this project would be an expensive headache, but hopefully in the end everything will all be sweet.
P.S. I'm would not run the spacer for my intended end purpose but for now it's a cheap fix until I get the rest of the car up to par.

 

10 bolts didn't have 2.77 gears, 9 bolts did.

Miles

 

My bad 88 427, should have typed 2.73 instead of 2.77. I had bought a 9 bolt disc brake originally from this other guy but could'nt find parts for it and then Summit & Jegs both said they were weak so I got rid of it. Ain't hind sight a bitch!