I bought Edelbrock header set # 6876 that's designed for dual CAT cars and comes with two pipes to weld to the stock exhaust. However I am wondering if it would be better to exchange this set for set #6872 (single CAT design) which comes with a Y pipe already assembled in one piece, and has a 3 inch outlet. Then I can remove both CATs and run one CAT with 3 inch inlet instead of 2 CATs with 2.5 inlet. Would the single CAT conversion flow better than the dual CAT setup? The Y pipe for single CAT cars has mandrel bends all throughout the length of the pipe. But if I cut and weld the pipes from the dual CAT set I will still have some stock pipe left in the car without mandrel bends and therefore will probably hurt performance. Please help I wanna get this over and done with but I can't until I decide exactly what kinda pipe will give me the best gain with my headers. Thanks

 

Dual is better. Just more expensive.