8.25 to 8.75 rearend swap??

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superdart

superdart

Shade Tree Tinker Gnome.....
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My 360 powered Dart has an 8.25 open diff with 2.45:1 gears.
My plan right now is to rebuild the current unit with a limited dlip and 3.55 gears. My car will probably never see more than 400 HP, so I figure this should do me fine so long as it is built right with the right parts. I think I'll spin the tires before I'll snap anything in the driveline.

HOWEVER - I just got a line on an A-body 8.75 housing with axles, brakes, lines, etc, for $125 plus shipping. Only the center is missing.

I know I would need to get aftermarket axles since I have 5x4.5 bolt pattern.
What else would I need to change?
Would my driveshaft need to be cut down?
What would I need to do for big bolt pattern brake drums? Would 8.25 brake hardware fit? Or would I have to hunt down 8.75 brake hardware from a B- or E- body?

Is it worth it? This is not meant to be a race car, just a street rod that would see the track ONCE IN A WHILE. If I keep the 8.25, I only need a new sure grip unit with gears, and a good rebuild kit (shims, clips, bearings, seal, etc.)

HELP!!!!!
 
I am going through the same issue right now. My dart has a 360 with 400HP and its more of a street machine than a racer.

This is what I have been told:
8.25 should easly hold up to a 400HP.
There is quite a few big blocks out there that have a 8.25 behind them.
8.75 rear will rob you of 20hp also.
8.25 I have been told are cheaper to rebuild
 
Your driveshaft will need to be shortened

You can use your 8.25" drums and backing plates and shoes, but you must specify to your axle supplier that you will be using the big bolt pattern hardware as the distance from the axle flange to the housing flange is different big bolt to small bolt.

Worth it? Absolutely...
 
Shock plates and U bolts are the same. It is the 7.25 that has the smaller ones.
 
340duster said:
Your driveshaft will need to be shortened

You can use your 8.25" drums and backing plates and shoes, but you must specify to your axle supplier that you will be using the big bolt pattern hardware as the distance from the axle flange to the housing flange is different big bolt to small bolt.

Worth it? Absolutely...
Click to expand...

I was wondering if you could use the 8.25 backing plates and put in the 8.75 shoes?
 
Wow, this is an old thread.....LOL

Since it's here, these are my current plans:

3.55s (Used from Dakota V6)
8.25 Sure grip (late model 29 spline)
Moser custom axles (to account for spline difference, and they are not tapered)
TSM Rear Disc brake kit
LPW Diff Girdle cover and carrier stud kit.
 
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