Ive got a 71 Duster Slant 6 auto, 7.25 rear end. I just scored a 8.25 sure grip from a 73 Dart sport 340 4 spd car for $100 bucks. I eventually will drop a V8 in the car and im changing everything over to 4.5 bolt pattern. My question is.. will i have to do any modifications to the drive shaft or anything else if i just swap this rear end with the slant 6/auto still in it? Like I said, im dropping a V8 later on.. but for now im gonna use the slant 6.

Thanks,
Jon

You need the driveshaft from the Dart Sport and your existing transmission yoke. The 8 1/4 places the rear U-joint farther forward so you need a shorter driveshaft, but the 4-speed most likely has a larger slip yoke than your 904.

I hope you also got the U-bolts and the plates with the shock mounts from the Dart Sport. The 8 1/4 has 3" axle tubes and the 7 1/4 only has 2.5" tubes so the plates under the springs and the U-bolts are different.

_________________
Joshua

ok thanks for the info.. i really appreciate. I thought I read somewhere that you would have to modify the driveshaft to fit the 8.25 rear. Actually im in luck.. My brother bought the the Dart Sport minus the engine and trans, so ill be able to grab all that stuff you mentioned from out under it. Its a parts car so he doesnt mind me getting what i need. Thanks again for the info.

ok thanks for the info.. i really appreciate. I thought I read somewhere that you would have to modify the driveshaft to fit the 8.25 rear. Actually im in luck.. My brother bought the the Dart Sport minus the engine and trans, so ill be able to grab all that stuff you mentioned from out under it. Its a parts car so he doesnt mind me getting what i need. Thanks again for the info.