i still have stock leaf springs under my 50 chevy coup drives and rides better then my new chevy truck i know you did not ask this. but you would have alot of money and work to get aset up in coil over to ride and work better for the cost . the chevy truck 60sto70 set up was piss poor set up good for big time wheel hop . the Aor G body GM have a better 4 link set up or build a 3 bar . i built some set ups. and on lower buck builds i used rect steel tubing boring holes were you want a bushing weld round tubing in holes to fit the bushing O.D caps ends press a bushing in done