The Stovebolt Site Forums The Shop Area Engine Shop rearend change out

Will a mid 70' schevy truck rearend work in a 53 ad? I have a transmission already to go in.

Yes. I've seen a 73-78 Chevy truck rear axle put in an AD truck. Look at this site for donor axle measurements Axle widths I think that the moderator of this forum was goofing with later chey axles but maybe that was IFS only-- can't remember. Maybe he or someone else will advise you better.

macdougall, you talking about the whole axle or just the center chunk?

hello macdougall. i have seen many pictures of ad trucks with 70's rears on them. i beleive that those rears are wider than the stock one and the wheels will stick out of the fenders a little.you might also have to move the axle to a position a little further back to avoid the tires hitting the fenders. you will also have to change over to an open driveline as the original has a touque tube. the exception to these 70's rear axles is the one used on some of the blazers. they are narrower and might fit better. in most cases the spring perches need to be relocated to fit on the stock springs. thats about all i got for now . good luck.

bznhafdzn yes i want to replace the whole axle. and gay g i was told if the axle was some where close i can get spewcial rims to bring the tires in. thanks for the input.

I have a 51 1/2 ton with a 79 12 bolt 6 lug rear axle.With 225-15 tires on 7 inch rims the rear tires are nicely within the fenders, the axle is only an inch or so wider that the stock 51 axle.

If you want to keep your 6 lug pattern, find a rear from a 73-87 1/2 4WD Blazer/Jimmy/PU. The rear end in these trucks were about 1.5" narrower than the front (something about rear wheel travel staying out of the ruts of the front wheels), and they work great under an AD. If you find one, you will need to invert it and weld on new perches, and you're ready to go. I helped a buddy do this with his truck and it took us about three hours. The only problem he ran in to was his stock wheels did'nt fit quite right ....... he had a company in Denver (I've got the name if you want it) build a pair of stock looking wheels that were offset to allow for the larger brake drums on the new axle. Worked great.

Pool guy,
Why do you need to invert it? Wouldn't that make the brake cylinders be on the bottom, and the pinion bearing be starved for oil? Or does it spin backwards?

the 65-69 rearends are 1.5" narrower than the later ones.

Thats a good question 4ontheFloor ....... and one that I can't answer (yet). He (my buddy) got the idea from Mile High Classic truck parts in Denver, and we followed their instructions. I'll give 'em a call on monday and ask and post the answer. For what its worth, he's been driving his truck in the Dallas/Ft Worth metromess for over a year now, and it's still working great.

Thanks everyone for the imput and idea's i pulled my donor rear out of the frame yesterday. But i do still have a couple of questions? The stock springs are under the axle and the new rear had them on top. can i still keep them on the bottom with the new axle? And someone mentioned wheels, will my present wheels fit the new axle they are both 6 lug on are they a different pattern?
Thanks again for the help and ideas.

Couldn't you just switch the brake backing plates back to their original position?

Or by inverting it do you mean he just put the springs under the rearend rather than over like the original? Can't see how it would work otherwise.

Macdougal,
You will want to switch the springs to under. You can get new spring pads and weld them on. The wheels are the same lug pattern but they may have differant backspacing.

McDougall--

Yes. spring UNDER axle. There are some pictures on this thread of Camaro and Blazer axle transplants and how the springs were done: axle thread .Also good thread might want to read it given ur project. Importantly, these old vehicles have a very high center of gravity--spring over axle would make them dangerous when cornering or braking from high speed, like a SUV --turn turtle. Be safe out there--might even want to reasearch monoleafs for ur truck.

Sorry I am new to chevy old trucks thing and going to check out a 53 1/2 ton this week. What is an AD truck?? It suppose to have a 67-72 6 bolt posi rear in it already. Is it true that the early chevy trucks were narrower then the later 73 and up truck rear end?? Thanks Ed [email protected]

AD - Advance Design series Chevrolet trucks, 1947-1955.1 (to further confuse things, GMC called them New Design).

Thanks for the help on AD I have an old **** they got fancy with the bonus built. I have alot to learn about the chevy trucks. You guys would be happy to know that I put a chevy in my Bonus built 50 f1. I get in big trouble saying that on a **** site. OH WELL