Another question that I have and might be good info for this thread is to take note that the summit/jegs axhaust kits do not come with an H or X pipe at all...How does that also affect performance with out having either? And how much louder is it?
i went from 2 1/2 pipes with no crossove to a 3" x-pipe system and had to jet up two sizes on the primary side of the carb. definatley made a difference. as for the loudness i don't know for sure because i changed the mufflers too. i'm thinking it has to quiet it down quite a bit. before with no cross over you could be 10 feet behind the car and you could feel like a pop from the exhaust hitting your leg when each cyl. fired. with the x-pipe it splits it evenly in the two pipes and you have to get up on the car to even feel the exhaust now. its really weird..