Coilover springs do not fit into the top of the tapered chassis cavities where the rear shocks mount.

These extended-length upper spring perches solve the problem by moving the spring down where it doesn’t contact the chassis.

The perches are available for 2.25″ springs. Or you can add a 2.25″ to 2.5″ adapter to use 2.5″ springs.

They have a 14mm ID to fit Von Shocks, Bilstein RSR, HD, and Sport shocks.

Also available Super Extended Length Upper Perches for ’65-’71 cars.