73 duster 17" or 18" wheels ?

oi81b4uu812b4 said

I do have another question, yes my car does have the 7-1/4" rear. I am looking for a 8-3/4" and will be modifying the 7-1/4 for the time being so I can move it while work progresses. We are going to be doing a US Car Tool Mini Tub & Spring Relocation soon with the 7-1/4".

Without getting into what width your rear axle is mounting surface to mounting surface... I am assuming if I measured your 1/2" trimmed rear wheel lip to the mounting face of your rear axle I should be at 7"?? (Mine uncut is 5.5"). I am assuming the Mini-Tub will get me 14-1/4" of room over the 12-1/4" stock. I am aiming for an 18" x 11" +20mm Offset rim with the 8-1/4 rear. Later with the 8-3/4" I will just add a Hubcentric Wheel Adapter...

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My measurement from the wheel mount would be different, I use a 68-70 B-body 8 3/4 rear axle which is wider. My 18x10's have 7" of backspace. From the inner wheel tub to the trimmed quarter lip is about 13" on my car.

With a mini-tub you'll have no issues with an 18x11 as long as the backspace is correct for your axle and spring locations. As for the spacer, you have it backwards. The a-body 7.25 rear is narrower than the a-body 8 3/4 by a 1/2" per side. If you want the same rims to fit both rear axles, you'll need to use a spacer on the 7.25. If you size the rims for the 7.25 they'll stick out too far with the 8 3/4, so a spacer won't help. You have to size the rims for the 8 3/4 and use a spacer on the 7.25" to keep the wheels off the springs.