The 10bolt Weld

Most of us have 10 bolts under the rear of our cars, and looking around for a good 12bolt can be hard, and may not fit your buget. The 8.5 BOP is a very strong rear, with no "C" clips you could snap an Axle and not worrie about the tire and snaped axle taking out your rear 1/4, and sending you into a wall or worse.

The 10 bolt that Chevy uses is not as well built haveing "C" clips and a case thats not as strong as a BOP.

First inspect the housing for straightness and to make sure there's no rust where the axle tubes join the iron centersection. To test the housing for straightness, set up the housing on a four-wheel alignment rack. Once you are certain that the housing is straight and sound, weld the tubes to the centersection.

All 10- and 12-bolt housing tubes are plug-welded to the centersection in two places. Drill six more holes on each side of the centersection, then weld them up. The idea is not to crack the cast, it has to be super clean. NOTE IF YOUR NOT A PROFESSIONAL WELDER, TAKE IT TO ONE, OR WARPAGE CAN HAPPEN.

The use of 35-spline axles, C-clip eliminator kit, (BOP have no C clipsand set the backlash tighter then factory spec of .008 inch, opt for the .0045-.005 inch. also go for max tooth contact on the drive side of the gear.


Not all GM 10-bolts are created equal. The key to longevity is finding the right axle housing. There are several different styles. The one with the 7.5-inch ring gear, common to the '82-'94 Camaro and firebird, is the weakest of the lot. The '64-'72 10-bolt in the Camaro,Firebird,Chevelle,Nova measures 8.2 inches accross the ring gear, so stay away from that one also. The 8.5-inch version is strongest, and it's indigenous to a variety of GM models ('70-'75 GTO, Camaro, Chevelle).

Other then measuring the ring-gear dimeter, there's no easy way to tell them apart.

The following chart lists the year and model of the cars with an 8.5-inch 10-bolt. Many of these applications will fit older models. For example, a '70-'72 LeMans,10-bolt will go right under a '64-'67 LeMans, even though the later housing is slightly wider then the one it replaces. You mayhave to change your spring perchs.

*Buick Apoolo '73-'77
Camaro '70-'81
Chevelle '70-'76
*Firebird/TA '70-'81
Grand National '84-'87
*GTO/LeMans '71-'77
Impala '71-'77
Monte Carlo '71-'77
Nova '70-'75
*Olds F-85 '70-'76
*Regal '73-'77

*Note all Buick Olds Pontiac are stronger dew to extra casting and no C-clips.