The primarries are 2 1/8" to 2 1/4" step with a 4" collector and side pipes. Some Gordon notes below:
The short list;
600+hp 460 with TFS A460 race heads
T600 road race trans
Live axle w/3:55 gears and Levy 3 link Watts
4 wheel Koni double adjustable
LR comp bump kit
A/C
Oil to water heat exchanger
NASCAR block and filter adapter
LR radiator
Full custom headers and side pipes