81 Malibu classic rear end HELP!
- Thread starter Shannon1978
- Start date
- Status
I have done a 7.5 with 8.5 28 spline axles and late style posi...figure $275 for the posi and $275 for axles....good to 11.50s before it let go...by the way, it has c-clips. The 8.5 is $850-up I have never been able to find one complete for less...still has c-clips. I did an 8.8 swap, wonky geometry, Mustang back wheels...then bought a Baseline Suspension swap kit was $320 to correct the upper control arm deal, then some weld on mounts for the lower control arms for $120. Oh, then $270 for 9 inch 31 spline axles and $80 for 9 inch axles ends that would accept the 8.8 rear disc brakes. Then $120 for a 31 spline spool plus some bearings.
The Chevelle 10 bolt and 12 bolt deal also requires geometry attention and now everyone thinks those rearends are worth $400-$1200...still has c-clips and the same size 28 spline axles, AND requires a funky offset rear wheel to work and never looks right.
I tried all the cheap ways...just buy the 9 inch and be done. 31 splines and a dirt track spool with normal gears went as fast as 9:90s with a big block no issuse after almost 10 years of abuse. Just stepped up to big axles, aluminum pro bolt thru case etc to go with a 632 its around 5.20's in the 1/8th now with the same housing, we did add a back brace.
The Chevelle 10 bolt and 12 bolt deal also requires geometry attention and now everyone thinks those rearends are worth $400-$1200...still has c-clips and the same size 28 spline axles, AND requires a funky offset rear wheel to work and never looks right.
I tried all the cheap ways...just buy the 9 inch and be done. 31 splines and a dirt track spool with normal gears went as fast as 9:90s with a big block no issuse after almost 10 years of abuse. Just stepped up to big axles, aluminum pro bolt thru case etc to go with a 632 its around 5.20's in the 1/8th now with the same housing, we did add a back brace.
Last edited:
I'm rebuilding my 10 bolt right now, 8.5 out of a grand national, 340 gears the posi was great off the line, around cones only one wheel was grabbing, picked up a eaton trutrack, 373 motive gears and moser axles, I'm in rhode island if your close by
I'm rebuilding my 10 bolt right now, 8.5 out of a grand national, 340 gears the posi was great off the line, around cones only one wheel was grabbing, picked up a eaton trutrack, 373 motive gears and moser axles, I'm in rhode island if your close by
We went the 8.5" route as well. When we tore it down I saw those puny 28 spline axles and decided on an upgrade. Maybe they'll hold up, but they are marginally larger than the stock 7.5" axles. At your HP level, I'd recommend a set of Moser or Strange axles at a minimum. Perhaps someone else can pipe in with some real life experience with your kind of HP and the stock axles.
Also, the 'low mile' 8.5 we bought needed a complete rebuild and we wanted different gears as well. So we ended up buying a 31 spline posi, bearing kit, gears and axles from Quick's. It saved about $300-350 over buying a complete 9" setup. I'm not sure that the $300 saved was worth it or not.
Also, the 'low mile' 8.5 we bought needed a complete rebuild and we wanted different gears as well. So we ended up buying a 31 spline posi, bearing kit, gears and axles from Quick's. It saved about $300-350 over buying a complete 9" setup. I'm not sure that the $300 saved was worth it or not.
I sold this engine about 10 years ago and gave all the build info with it including the dyno sheets. It had 990 heads w/ quite a bit of work done and I had 2 big solid roller cams and can't remember the spec's. Tried looking @ pic's I had but the numbers are covered
- Status
