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| | | | Joined: Dec 2010 Posts: 41 New Guy | | New Guy Joined: Dec 2010 Posts: 41 | hey people,new on here,great info,does anybody know how to id rear end on 1965 chev shortbox,been looking around but nothing for trucks that i have seen,only numbers i have are 3856525,and stamped on axle housing is MHA?and also it is 12 bolt truck rear,pretty sure of that when doing research,8.875 12 bolt,can these numbers tell me gear ratio?how can you tell if posi?thanks,,new kid on site, | | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | MHA is the code for a 3.73 gear. Usually, a Posi differential will have a tag on one of the cover bolts stating to "sue limited slip fluid only", but it's not unusual for those to be missing. To check without taking the cover off, jack the truck up and support on stands, put the trans in gear (any gear will do), then turn one of the wheels (doesn't matter which one). If the other wheel turns the oopsite direction, it's an open diff, if you can't trun either wheel, it's a Posi. Most likely, thouhg, you have the open differential, which as far more common.
Bill Burmeister
| | | | | Joined: Dec 2010 Posts: 41 New Guy | | New Guy Joined: Dec 2010 Posts: 41 | sounds good,thanks for the info,,would it be possible to make this rear posi? What does (sue) mean?Ive seen posi units to install into rear on internet but is that the way to go,also is that rear strong,want to put some power to it in the future,,thanks again,Robin | | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | Whoops. That was a typo, meant to say "use" rather than "sue". There shouldn't be any issues with installing a posi ir even a locking differental such as a Detroit Locker, there's several on the market. Strength shouldn't be an issue, the 12 bolt rear uses the same internals as the passenger version, which saw use behind some of the most potent muscle cars from the '60s/'70s, including the Yenko Camaro, Chevelle, and Nova, all well over 500 horse, the 450 horse LS6 '70 Chevelle, and quite possible the baddest of the bunch, the '69 ZL1 Camaro, which was well over 650 horses.
Bill Burmeister
| | | | | Joined: Dec 2010 Posts: 41 New Guy | | New Guy Joined: Dec 2010 Posts: 41 | great info,,,thanks alot long box,good to know!! | | | | | Joined: May 2009 Posts: 47 New Guy | | New Guy Joined: May 2009 Posts: 47 | I have a 65 GMC with a 425 hp 350. The truck has the stock 12 bolt 373:1 gear ratio with the open diff. I can easily do 125ft. burnout on the go and the truck always goes straight. Nothing wrong with limited slip as far as i am concerned. The factory rearend is strong and can take the abuse. | | | | | Joined: Dec 2010 Posts: 41 New Guy | | New Guy Joined: Dec 2010 Posts: 41 | I have another 65 truck with 12 bolt also,,the stamp on it says HA3,,,can someone tell me the ratio in that truck,thanks, | | |
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