Confused on which rear end to replace 7.5 with

[Piper5314]

I AM BUILDING A 85 ELCO & HAS BEEN MANY YEAS SINCE I HAVE WRENCHED ON CARS
I HAVE BEEN READIND THE THREADS ON REAR END REPLACMENTS,
MOTOR GOING IN IS A 383 STROKER APPROX 520 HP NOW THE REAR END THAT CAME WITH CAR IS A 7.5 10 BOLT 343 POSI LOCKER AFTER READING THREADS IM CON VINCED I NEED A STRONGER REAR END SO WITH THAT B EING SAID WHAT SHOULD I BE LOOKING FOR THAT WILL BOLT IN WITHOUT ANY FAB HAVE ACCESS TO A 10 BOLT OUT OF A 71 CHEVELLE WILL THIS FIT APPRECIATE ALL ADVISE

Looks like you need to sell me that old 7.5 you're taking out. I need one, and I'm not ever going to see a track. I'm in TN, where are you located?

its a 7.5 posi out of 85 el camino I will let it go pretty cheep but shipping could be expsive palm springs ca. dave 760 673 9618 or 760 3451607

Wow, you are right on the freight. Time I paid freight, I could have put a 9" in it. Thanks but I will have to keep looking closer to TN.
Marty

 

[david lehman]

Your rear most likely has 3.42 gears, not 3.43 and while its generally not recommended you can put some power through the gbody 7.5s, but its not worth the risk even if you go all out and build them up. A 10 bolt from a 68-72 CHEVROLET a body like s Malibu/chevelle will fit but you will need custom upper and lower control arms because that rear end is about an inch or so wider on either side. UMI makes upper and lower arms that are adjustable and have heim joints to avoid binding. If you wanna keep it gm but want it to be bullet proof, get a 12 bolt from a 68-72 CHEVELLE. The BOP rear ends are different and won't fit. In short, that 10 bolt chevelle rear will work, just rebuild it first. Gears, axles, new posi unit, gaskets, bearings, etc.

ok this is my last ? on rear end swap I am ready to pull the trigger on a 8.5 55 in plate to plate came out of old pickup I will rebuild the whole thing with new axles,373 dif & posi locker bying the 8.5 cheep my ques is there anything else I need to do other than buy ajustable trailing arms & move the spring perches

 

[565bbchevy]

I need a stronger rear end so with that being said what should I be looking for that will bolt in without any fab?

So I am guessing this comment doesn't apply anymore.
And getting something "cheap" doesn't always end up being the least expensive solution.

 

[Texas82GP]

GM trucks in the 60's had rear coils with truck arm suspension.

 

[565bbchevy]

I don't see any listing on UMI's site for rear control arms to mount a truck rear end in a Gbody.

These control arms from UMI Performance are designed to bolt a 1964-1972 GM A-Body 10-Bolt or 12-Bolt rear end into a 1978-1988 GM G-Body; this includes Monte Carlo, Malibu, El Camino, Regal, Grand National, Grand Prix and Cutlass. These upper control arms are built at the correct angle to attach to the G-Body chassis as well as the A-Body rear end "ears". These control arms are a must any time this swap is being completed. Using factory control arms will cause drastic rear end bind and incorrect driveline angle, this leads to traction lose, vibrations and unsafe handling.

 

[el corvino]

I have one of everyone rear end under all my high performance G-Body's (except the anchor weight 7.5) I'd never buy and build the 8.5" again because for the cost of the unit, and all accessories to build it properly... stick with a strange or a 9". Learn from my earlier years mistake and do it right the first time and be done.

 

[Turbo Zach]

A 1970 cevy half ton two wheel drive had those. They were six bolt I do believe. The control arms were really long. I would stay clear of those! I would go with a mustang 8.8 or a QP 9 inch.

 

[Texas82GP]

thanks, I didn't know that, I wonder what truck his rear end comes from...

Happy to help. The 67-72's, and if I'm not mistaken, the generation before it all had that coil spring/truck arm suspension.

 

[565bbchevy]

I am thinking the OP should probably stick to something that is a direct bolt in requiring nothing special to mount it or any modifications to rearend itself either an 8.5 Gbody rear or any of the aftermarket bolt in 9" or 12 bolt units etc.

 

[lilbowtie]

You can take a horse to water but you can't make it drink.