I welded in some plates today that i made to get rid of the stock rubber pads in the leaf spring perches. I made some rectangular metal pads and drilled a 1/2" hole in it that located the leaf spring pin in the stock place, then i welded in the plates into the leaf spring perch. the leaf spring sits great in the perch but how do i control the lateral movement, there is about 1/8-3/16" gap on both sides of the spring inside the perch. any ideas how to fill the gap so there is no play?

stuff some shims up there made out of 1/8" steel plate and weld them in.

I wouldn't be too concerned about it. Any lateral movement will be limited by the pin on the spring.

Yes, but, without a filler between the spring bolt and shock plate hole, there still is a space.

Clamping of bolts, whether U-bolts or T-bolts, on spring perches is not enough to keep the axle from moving on the spring, it needs the spring bolt-to-plate ridgidity.

Look at all the non-GM spring perches, they have no sides at all! The center bolt will hold it as long as your shock plates clamp it well. One problem with the single leaf plates is, they are pretty thin.

I'd weld some reinforcing strips from left to right to stiffen them, or they will usually bend in the middle. The multi-leaf plates are better, but won't work on a 67 on the left side beause the shock is in from of the axle.
David

The spring is sticking out enough for the shock plate to clamp it well, this is on a 71 firebird, and i will get the multi ieaf plates since my olds ones are all bent! the movement i am speaking of is on the sides of the spring inside the perch, i think novaderrick hit it on the head by putting in 1/8 shims, that might work.