I have 12 bolt type(O) 28 spline axles.Have problems finding posi unit that will work in it.I have bought 2 different ones on ebay, 1 was 8.2 with 3.08 gears and pinion.it will bolt in but the pinion is different.I also bought 8.5 posi unit but my factory 278 gear wouldn't(10) bolt up to it.I traded it for a set of B heads.Anyone know of anything that will work without changing the whole rearend,and not to expensive.Thanks for any suggestions!!!

 

"Reider Racing" has them. It is a 8.8 Ford unit machine to fit. I've done 2 of them and they work fine.

Gene

 

No, you don't. You have a TEN bolt Type O. Contrary to popular believe, the number of bolts on the cover is irrelevant. The ten/twelve bolts designation refers to the number of bolts holding the ring gear. On Chevy axles, the number of bolts on the ring gear and on the cover happen to be the same. On the Type O, they are not. A true twelve bolt axle has twelve bolts holding an 8.875" ring gear to the carrier. The Type O has ten bolts holding an 8.5" ring gear. You need a carrier for a Type O. I was not aware of the modified Ford carriers being modified to fit. That is pretty cool.