Centering the rear wheels

[72BlueSwinger]

Hey. This may be a dumb question, but since I just searched through 16 pages on here with no results, I'll ask it anyway. I am going to swap out the 7 1/4 in my 72 dart to an 8 1/4. I know the driveshaft has to be cut down by about 1.5 inches. I had already thought about trying to move the rear axle back about the same distance, so I could run a little larger tire in the wheel well if I wanted. Is there any way to do this SAFELY? I figure you could get a spacer made for the front spring bracket fairly easily. But what about the rear spring mount... AND how would that effect an inboard spring relocation kit? Thanks ya'll.

 

[340duster]

If you put too large of a spacer in the front spring mount you could run out of shackle travel at the rear mount. The rear mount cannot be moved without some cutting and welding. To move the whole rear end back 1.5" will be too much anyway to gain wheel clearance. It will look funny too. The oval track rear springs from mopar performance have the pins moved back an extra 1/2" for tire clearance. So I think 1/2" back would be a good number to start with.

 

[rowinafour]

I moved mine back by drilling another hole in the spring seats. You must also drill a hole in the shock plates the same amount to allow the u bolts to line up properly. This allowed a 28 inch diameter tire to be used without cutting the front lip on fender. It also centered the tire in rear fenderwell. Be prepared to lengthen driveshaft.

 

[flyboy01]

I agree, 1/2 is safe, plate might work, but you have to have enough length in the studs. I would not go with less than the nut thickness of threads sticking out of the end.

 

[72BlueSwinger]

Hey Rowinafour, how far did your setup move the axle back? I won't need to lengthen the driveshaft because it is already too long for the 8 1/4 rearend anyway. And I live near a hardware store, so longer bolts won't be a problem.
The reason I'm looking into this is because I'd like to have a bit of a larger tire, but mainly to avoid having the driveshaft shortened. Looks like I'll be doing that anyway, though. and I was hoping to have everything driveable by this weekend, or next weekend. I may just keep the 7 1/4 under there for a bit longer. The Dart isn't quite road worthy yet.

 

[rowinafour]

I do believe it was an inch. In fact, some spring seats have extra holes that can be used to move the rear forward or back. Again,you must redrill the shock mount to reposition it properly align the u bolts. This requires a spacer to be welded on the mount to allow it to seat against the springs flush.