It seems the kits advertised as 3/4 " may not be. Some have mentioned this. The kit I bought,and my install put the springs slightly inboard of the factory tubs, which is all you need to maximize room in the stock tubs. I bought a Chrysler kit. I had to put holes in the frame rails to accommodate the bolt-heads. Then of course I had to relocate the perches on the axle tubes.I leveled the frame and dropped plumb-lines from a 3/8 inch spacer(for tub to sidewall clearance), on the inner tub walls, then located the perches as far as I could towards the plumb lines, without the springs intruding into the tire space. There I clamped it down. Then I lowered the car to it's normal ride height and set the pinion angle. While doing all this, I kept an eye out for where the outer sidewall was going in relation to the outer fender lips, to maintain the entire pkg was centered in the tubs. In this way, I was able to fit 325/50-15s in stock 68 Barracuda tubs. Just barely. They worked fine in most situations, but with spirited cornering they would occasionally rub on the inner tub walls. I determined the area of offense and took the bfg to it,problem more or less solved.lol
