I just purchased a new posi and gears out of an 87 iroc and im looking for a new diff cover and gasket. My question is,what size rear end do i have? i keep seeing them at 7.5 & 7.625 . i have an 86 iroc z that currently does not have posi and what i beleive to be a 2.73. o and its tpi if that matters . any help is appreciated

 

that would be a 7.5 inch rear but most covers for either or are interchangable. Since the bolt patterns are the same.

 

ok thanks for the help

 

Not just the bolt patterns, everything is the same.

 

if everything is the same, why do they have different names>?

 

Gm likes renaming things

 

.... Trust me i work at a gm dealership, and everything has like 4 diffrent names and it always is the same part just different car.. Its a big pain when trying to get parts from the parts shop and they all give u a odd look then u name off the 3 other names and they finally relize what you are talking about.

 

Some of the 10 bolts have ring gears that are 7.5", and some are 7.625". The extra .125" makes no difference to anything else, and the two different sets are interchangeable.

Usually the 10 bolt is just referred to as the 7.5" rear, and it's understood that this includes the possibility that the ring gear may actually be 7.625". If there is explicit mention of 7.625", it's almost always together with the 7.5", as in "7.5/7.625" differential".