Rear end for J body

[Doubt_Incarnate]

if i did this swap id be trying to make one hell of a 2.8. mostly just to show what gm's tiny v6 can do. so a 9" is probly overkill, and its ford. its a project on paper so far, probly wont actually happen for quite a few years. most likely the 2.8 pushed to its limt N/A probly wont break a 7.5"gm, chances are it wil probly come down to weight between the possible donors. id really like to mix and match gm parts around to come as close as possible to the right width, and if i need to flare the fenders a little, no biggie. rather not have to have customs parts made, so if in the event i break something like an axel, i can just go pull one and not have to special order stuff.

i was hoping since the s-10 have a rwd offset wheel (wheras i dont the blazers do), that the axel would be narrow enough i could put a set of fwd offset wheels on it and come out to right width. i saw the dimensions are about 54" from face to face of the wheel mount, i remeber measuring the inside of my truck from inner quater pannels its right about 60" wide si i think the s10 axels with a fwd offset might be what the doctor ordered, but i wont actually know for like, 5 years... once again, thanks for all the helpfull info.

[smilinguy99]

if i did this swap id be trying to make one hell of a 2.8. mostly just to show what gm's tiny v6 can do. so a 9" is probly overkill,

Then use lightweight components, swiss-cheesed spool, gun-drilled axles, thin gauge axle tubes.

Or perhaps an 8" Ford.

Whatever you use, I wouldn't shy away from making it the right width if the piece you find isn't correct.

[Doubt_Incarnate]

i still want to stay "all chevy" with my car, the furthest i'd stray is going with a dana from a jeep wrangler. i'm sure since there are thousands of gm's 7.6xx rear ends there has to be someone out there with parts for that.

[bszopi]

Not really why you are so stuck on Chevy for this thing. I bet if you look under a lot of street rods and muscle cars out there, you will find Ford 9" rear ends. This is because they are a very strong rear end and and sg99 stated, parts for them are plentiful with even custom parts being affordable.

[Doubt_Incarnate]

cuz i want it to be chevy stuff. i understand it is an option. but if i can stay away from it, id like to not have ford contaminating my chevy. my explorer does its job well enough, so its not like i hate ford. I'm just trying to not have a mutt of a car. like a chrysvrord or a toyonda. mazdodge

[sharkey]

using a ford 9" rear doesnt give you a mut of a car. the 9" is lone of the best rear ends out there. id take a 9" over a gm 10 or 12 bolt any day. a dana 60 is also an ausome rear as well.

another option might be a dana 44. they are a tough rear end as well, but smaller and lighter, and if you are looking at a high hp v6, it may be the ticket.

[Doubt_Incarnate]

i was also thinking it might be best to do an independant rear setup, i'd like to keep the weight between the axels, so the front of the motor would have to be on or behind the front axel line, that might make a really short driveshaft that wouldnt like to move. if i can find a gm axel in a yard that is about what i want, why would i build a 9"? what would it cost to make a custom 9"? say a couple hundred for the tubes, and another hundred for bearing plates, then a carrier, and the axels... looks like the 2wd s-10 axel is 54", and my car is slightly over 60", im sure the wheels would take up the remaing 3" on each side. i'd rather just pull that from a yard than build a ford 9" for 2-3 times the price. but i have to get under the car to see about the driveshaft length, if its too short, there is no need to find a solid axel. I'm sure the ford is tough as hell and is great in ultra torqy muscle cars and things that need to stand up to hard work and abuse and 500+hp. but there is no place for that in my car, at best it would be holding up to 270hp or so, and propelling a mere 3000lbs or so.

[geoffinbc]

Ok guys what the hell do you think Doubt is running here? Dana 60, GM 12 Bolt and Ford 9" is stuff made for a 1 ton. You can ram 600 HP through a 7 5/8" with just a descent LSD like an Eaton. Take into account a light vehicle that will never get traction with that much horsepower anyway and you have a combo that will never break and if it does all he has to do is hit a scrap yard. The LARGEST I would go with would be the 8.5" and the plus is he can find it in his desired width and with disc brakes. How can you go wrong there?

Stop suggesting rediculous parts that are out of budjet and out of reason.

[Doubt_Incarnate]

somone gets it.

[Guest]

Ok guys what the hell do you think Doubt is running here? Dana 60, GM 12 Bolt and Ford 9" is stuff made for a 1 ton. You can ram 600 HP through a 7 5/8" with just a descent LSD like an Eaton. Take into account a light vehicle that will never get traction with that much horsepower anyway and you have a combo that will never break and if it does all he has to do is hit a scrap yard. The LARGEST I would go with would be the 8.5" and the plus is he can find it in his desired width and with disc brakes. How can you go wrong there?

Stop suggesting rediculous parts that are out of budjet and out of reason.

Yep. I agree.

I've seen a 3800 lbs Firebird (2nd gen) go LOW 10s on the ORIGINAL 7.5" rear end, gears, axles and all. Oh yeah, that was a BBC powering that ride too.

The 2WD S-dime rear is the absolute closest to fitting. The difference is measured track width is 1/2" narrower IIRC. That is using the 2WD S-10 wheels. When I was building my RWD Sunbird, I had the axle under the car and it was very close. Unfortunatly I didn't get around to cutting out the spare tire well or the inner wheel wells to fit it closer.

Oh and if the Ford 9" is so great why do places like Bear's sell a pumpkin that allows you to use a GM 8.5" diff and gear set, in the 9" housing?

[geoffinbc]

somone gets it.

You were looking alone out there.

LOL I was waiting for someone to suggest a GM 14 bolt or GM/Eaton HO72 rear end.

[smilinguy99]

Strength is secondary. Agreed. The original post stated he wanted to use a production axle, and "hope everything comes out to be the right width."

Sounds like saving money is primary. A 9" is a cheap alternative and could be made to the exact width very cost-effectively.

You don't have to use the big bearings or the big axles, or the mega dollar R&P, or spend tons on a high dollar diff or put all the best, most expensive goodies in it to make it perfectly bullet proof.. Just cheap production stuff will do. And if you need to upgrade later, there are a huge number of options there. Can't say that for most rearends.

Lots of decent machine shops could do the work of shortening most any rear end for less money than the original poster probably thought. But a custom 9" would be very cost-effective too.

Get it?

sg99

P.S.

Oh and if the Ford 9" is so great why do places like Bear's sell a pumpkin that allows you to use a GM 8.5" diff and gear set, in the 9" housing?

Uh, to give 9" users yet another option? Thanks for helping to prove my point.

[Guest]

Strength is secondary. Agreed. The original post stated he wanted to use a production axle, and "hope everything comes out to be the right width."

Sounds like saving money is primary. A 9" is a cheap alternative and could be made to the exact width very cost-effectively.

You don't have to use the big bearings or the big axles, or the mega dollar R&P, or spend tons on a high dollar diff or put all the best, most expensive goodies in it to make it perfectly bullet proof.. Just cheap production stuff will do. And if you need to upgrade later, there are a huge number of options there. Can't say that for most rearends.

Lots of decent machine shops could do the work of shortening most any rear end for less money than the original poster probably thought. But a custom 9" would be very cost-effective too.

Get it?

sg99

P.S.

Hmm, let's see here, let's break it down, shall we?:

GM 7.5 (or 7.625) from a 2WD S-series: $200 (approx, from wreckers)

Ford 9" : $250+ (from wreckers)
Narrowing: $300 (cheapest I've found) If the axles are the right axles. In most cases, the axles need to be from a different car, so that they can be resplined.
Bolt pattern change (If desired to match front): $50 to $75

Using the GM 7.5/7.625 $200
Using the Ford 9" $600+ (the cheap way)

Which one will work better? The GM axle, why? The moment of interia will be lower, taking less power to turn the wheels, It fits a hell of a lot easier, since it's already the right width, and in a light car, a 7.5 will hold up to abuse very well.

Oh and if the Ford 9" is so great why do places like Bear's sell a pumpkin that allows you to use a GM 8.5" diff and gear set, in the 9" housing?

Uh, to give 9" users yet another option? Thanks for helping to prove my point.

Nope, not why, you should really do more research before you think that I was there to prove your point.....

The reason is because the 8.5" has a lower momonet of inertia, to take less power to turn, also the gears mesh quicker, for more mesh of the gears to make for less brakage.

[Doubt_Incarnate]

so the s-10 axel/wheels is a 1/2" narrower?, or is the j-body axel?

The 2WD S-dime rear is the absolute closest to fitting. The difference is measured track width is 1/2" narrower IIRC. That is using the 2WD S-10 wheels.

im sure there are a ton of great options for rearends out there, but lets not turn this thread into a flamefest and get it locked.

[Guest]

The S-series rear has a 1/2" narrower track width than the J-body, IIRC.