Grand Rock Bed Kits for dual stack installation.  Designed with ID outlets for use with stacks that have a 4 inch OD Outer Diameter base. The T-Pipe adds approximately 10” of length (or height) to the stacks when mounted in the bed. Only one hole needs to be cut in the bed, where the T-Pipe inlet goes down through the bed to connect to the under-bed piping (also included).

All the piping in the kit is commercial grade aluminized steel. All clamps are heavy duty and Zinc coated for durability. The kit piping is 4 inches though-out.  For exhaust systems less than 4 inch, a heavy duty aluminized exhaust reducer/adapter will be added when you select your exhaust size.