The slippery "tape" (for lack of a better term) that you put between the spring leaves to quiet it down and soften the ride a bit.

I've got the rear springs apart on the 49 and will take out every other leaf and put the tape between the remaining springs.

The proper technical name would be helpful too.

 

speedway - leaf spring liner

spring liner from Speedway Motors, America's Oldest Speed Shop

Make sure to grind off any grooves left from the old springs. If you don't it will rub holes in the liners at that point. Cut them down with a grinding disc and smooth with a flap disc. Don't over heat them.

 

I just ordered some from Classic Haulers/Mid-fifties. I think it was $21 for enough to do a pair of springs.

 

I bought mine from a local spring & brake shop. The stuff I used was made for leaf springs and is called delrin. You have order it to suit the width of your springs and it came in a roll. You just cut each piece to length.