Novice needs help

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Saetun

Saetun

Sinister Swinger
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Looks like I may have located a 8.25" sure-grip rear end that I can pull a donor center section from. The guy selling says it's an 8.25" w/ 3:23 (assuming 3:21) from a '71-72 B-Body. My question is; is the center section a straight up swap into my '73 Swinger 8.25". If so, here's the real novice question... Do I just slide the axles out a little & unbolt the center section & it should just drop out? I've never been inside one of these but I'm assuming I can make the swap myself. Any help or guidance would be much appreciated. If I'm way off on the whole deal, please straighten me out. Thx.

~Jeff
 
8.25 is NOT a "drop-out"...it has an inspection cover on the back? 8.75 has a drop-out center section. You could probably swap the whole housing into your Swinger, if it's the same overall length.

Top pic is 8.25...bottom is 8.75.......


If you want to swap gears to your housing, you will have to swap the other pinion as well. To change carriers will require special tools and new shims.
 

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I think he's describing the actual differential. If I understand correctly , he wants to pull the half-shafts out enough to clear the side gears. Remove the carrier bearing caps and pop out the diff. The trick is what ratio do you have in your housing now. If you're using your gears , you have to have a ratio bigger than 276 , there's 2 diff's 276 and higher, the there's the 245. If you're changing gear sets you gotta take the pinion out too..............
But then if you got a 8&3/4 it all drops out together.
 
funwithfuel said:
I think he's describing the actual differential. If I understand correctly , he wants to pull the half-shafts out enough to clear the side gears. Remove the carrier bearing caps and pop out the diff. The trick is what ratio do you have in your housing now. If you're using your gears , you have to have a ratio bigger than 276 , there's 2 diff's 276 and higher, the there's the 245. If you're changing gear sets you gotta take the pinion out too..............
But then if you got a 8&3/4 it all drops out together.
Click to expand...

Yes, I'm trying to go from 2.94 open carrier to originally a 3.55 sure grip. I came a across the rear end from a b-body with a 3.23 sure grip & just am trying to see if its a straight up swap & if its remedial enough for me to pull off myself. Thank you.
 
Yeah , should be straight up swap . If you've got your half-shafts out make sure your splined end goes into the side gears. I think , in addition to different carrier halves, there are 27 & 29 spline side gears. There's a tool for adjusting the carrier bearing / adjusting ring/pinion contact. I see em on eBay and a fella on here made a bad-*** one from common materials. Check your backlash prior to disassembly , gives you a starting point to shoot for when you put your gear on that other carrier. Please use new ring gear screws. Cheap insurance against premature failure.
 
Okay, More rookie mistakes... Crawled under the car to check to see the gear ratio tag & lo & behold, no oval 10 bolt with 2.94 gears but a hex 9 bolt w/ 2.76 gears! Didn't make me feel very warm & fuzzy.

Since I'm doing a bucks down build which should net just shy of 300hp (288hp by a member's desktop dyno), should I even worry about having a 7.25 back there? Just swap the ring & pinion to 3.21 & drive it until it does or doesn't explode. Or should i pull the trigger on the B-body 8.25 w/ SG and mod it to fit. If I go with the B-Body rear, what steps need to be taken to make it work? I've also tracked down a peg leg 8.25 out of an A-body a few hours away but have to check on bolt pattern & such.

Could use some advice here as I don't want go into panic mode, as I have a tendency to do, & make a bad call.
 
i would go after the A body 8 1/4 myself. the 7 1/4 would "live" for a little while but its only going to take that one good burnout or launch and it will probably let go. IMO

thanks to the jeep guys , there are great options for the 8 1/4 rears

fyi..all 8 1/4 rears are 5 on 4 1/2
 
73AbodEE said:
i would go after the A body 8 1/4 myself. the 7 1/4 would "live" for a little while but its only going to take that one good burnout or launch and it will probably let go. IMO

thanks to the jeep guys , there are great options for the 8 1/4 rears

fyi..all 8 1/4 rears are 5 on 4 1/2
Click to expand...

Is the swap a simple unbolt the old & bolt in the new? I got caught up somewhere doing a little homework that the drive shaft length is different. Can sum1 confirm or deny?
 
Saetun said:
Is the swap a simple unbolt the old & bolt in the new? I got caught up somewhere doing a little homework that the drive shaft length is different. Can sum1 confirm or deny?
Click to expand...

yep 7 1/4

you will need to take 1 1/4 " out of your driveshaft for the 8 1/4

the 3.55 can be used in your new 8 1/4 by removing the gearset and the pinion. you may need to shim it and you will need a new crush sleeve
 
you know where drivelineservice is in sl?they are about a mile from your house.
 
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