[Owens1240]

Bought this nova. Guy said it had a 7.5 10 bolt from 75 nova with 3.42 gear. Is this a 7.5 or 8.5 from the rear cover?

 

[ranedig]

It kind of looks like an 8.5" based on this chart

 

[daveschevyparts]

8.5 housing. Has the 'ears' @ seven and five oclock positions.

 

[bracketchev70]

Yup 8.5. 8.2 had a ridge in the cover like the 12 bolt and a 7.5 cover is kinda square.

 

[firebird69racer]

according to this site, the 7.5" didn't come out untill 76, check out this site it has a lot of good info

NovaResource - Nova Rear Axle Codes

 

[mrlaze]

Looks like an 8.5 10 bolt to me as well because of the nibs on the bottom.

 

[RifRaf]

I agree with all posts above... definitely a GM 8.5" rear.

 

[Owens1240]

I agree with all posts above... definitely a GM 8.5" rear.
View attachment 415759

Thanks everyone! I thought it was the 8.5. So is this a good rear end?? Should I replace it with a 12 bolt or 9 inch?

 

[mrlaze]

Its fine unless youre going to have like 1000hp(I'm not 100% the cut off). I have a used one I will be rebuilding for my car with estimated Hp/Tq of around 450/450.

 

[RifRaf]

The 8.5" is a good rear end... and with some aftermarket items (axles, carrier), it can be built into a very strong unit.
The diameter of the pinion in a 10 bolt 8.5" rear is the same as the pinion in a 12 bolt rear.

 

[Owens1240]

The 8.5" is a good rear end... and with some aftermarket items (axles, carrier), it can be built into a very strong unit.
The diameter of the pinion in a 10 bolt 8.5" rear is the same as the pinion in a 12 bolt rear.

Thanks!! I'm only going to be running about 500hp. Probably going to shorten the rear so I will need to change axles anyways at that point.

 

[75novafromgrampa]

my 1975 Nova came with the same thing, its it is a 8.5

 

[Ericnova]

Thanks!! I'm only going to be running about 500hp. Probably going to shorten the rear so I will need to change axles anyways at that point.

Up the spline count from 28 to at least 30 when you do axles and differential....I'm not sure if anything bigger like a 33 spline is available.
Rear girdle cover.
Weld tubes to centersection, using correct rod for cast iron.(Nickle....or silicon bronze if you can TIG). Prep is key on this, so do your homework on surface prep.
It'll handle pretty much anything a similarly modified 12-bolt could handle..