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8 1/4 rear end-How much is it good for? torque/horsepower

Mopar Muscle
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8 1/4 rear end-How much is it good for? torque/horsepower

greymouser7 greymouser7
Enthusiast | Posts: 267 | Joined: 10/09
Posted: 12/30/10
10:07 PM

I have noticed that the rear ends in a lot of late model jeeps are similar to the 8 1/4 in my 76 volare road runner (E58) {360}
how much can I throw at it?
I found an 8 1/4 pinion snubber and a package sale of bearings and a sure grip unit on ebay.  I want to keep using this rear in my Aspen F body.  

drmopar drmopar
Guru | Posts: 1445 | Joined: 02/08
Posted: 12/30/10
11:42 PM

This is a surprising decent rearend that has been overlooked by most. Just beware when buying the posi, there are two different units. One for 2.41 and higher gears and one for the others. My brother has a 8 1/4 in his 14 second Duster. No issues. I have also seen them in a 12 second Aspen. The guy ran it this way for yrs. without any issue.
He has a 360 making 450 horse with slicks.
The C-clips on the mopar rear end cannot drop out like a chevy unit, so no need to worry about spitting out an axle.
Good Luck.  

68440Barry 68440Barry
User | Posts: 91 | Joined: 04/09
Posted: 01/03/11
08:28 AM

I have an 8.25 posi in my 74 pickup with a 67 440 and about 400 h.p. So far so good.  

yvdz yvdz
User | Posts: 118 | Joined: 12/08
Posted: 01/03/11
11:12 AM

Keep that 8 1/4, they are strong enough to handle a potent small block. Besides, they are WAY easier to find than a 8 3/4.  

RBolig RBolig
Moderator | Posts: 948 | Joined: 12/03
Posted: 01/03/11
01:18 PM

I have a 4.10 geared 8-1/4 in the Dart Sport with a 400 hp small block and a four speed, and it's having no problems.  

Some people are like Slinkys; they're not very useful, but fun to watch when pushed down the stairs.