85 monte carlo ss rear end suggestions

the nitro man

Amateur Racer
Jan 8, 2006
greeneville, tn
i have an 85 ss monte carlo & i'm building around a 400 horse 357. the car has a 7.5 3.73 gear, open carrier rear end in it from the factory. would one of those powertrax lockers be ok for it & it live, or should i get one for a 4.625 (7 5/8" if it will even fit in the 7.5 carrier) & get a set of 28 spline axles out of a 86 up g body rear.

this car isn't going to be on the drag stripe every weekend, it will just be a street car that i might take to the track a couple times a year.

i have found a after market nodular iron 9" ford center section, my choice of 3.70, 3.75, 3.80, 3.89 or 400 gears, 31 spline Detroit locker & a Daytona pinion support for $500.00 bucks shipped. seems like a steal, but then i would have to get the rear end housing & axles & then i'm in it for around $1,300 bucks. not to bad i know but i'm on a budget.

damn i hate being poor


Top Fueler
Jul 1, 2009
many years ago i had a 7-5/8 monte ss rear end and put a powertrax in it also.i wasn't making a lot of power but i did try my best to break it.i ran et streets with it too.it was on the cheap and worked well.


Top Fueler
Feb 21, 2008
Ontario, Canada
I personally wouldn't spend a dime on the 7.5 or 7.625 rear end. Correction....I DID spend a bunch of money trying to make my old 7.5 rear end "stronger", broke it almost instantly, and wished I would have just put that money towards something stronger from the beginning. I guess it's up to you, but I can tell you from experience that having "I hope it doesn't break" in the back of your mind all the time is no fun.

LS6 Tommy

MalibuRacing Junkie
May 15, 2004
North Jersey
Lots of guys say they do just fine with a 7.5". They just didn't break it YET. Get the 9"...


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