Slip on or full exhaust

[island400ex]

Hello, I recently had some head gasket issues, so while I have the head off for machining I figured I would also get a mild port and polish. It was bench flow tested and had a 30% increase in flow! Now I am looking to my exhaust, I currently running a pro circuit head pipe with a muzzy slip on. The head pipe is not much different in size to the stock header except the welds are flat on the interior, so would I benefit moving to a full system or maybe a better flowing pipe like an hmf?? Sorry for the long question.

Oh and by the way, it's a 416 11:1 comp wiseco, stage 2 hotcam, 450r carb, and of course mild p&p thanks

[honda400ex2003]

I guess i would say yes with that amount of increased flow. Otherwise I would say no. the 450 carb lets it breath good too so it would benefit from having a higher flow header. I would go with something like a sparks with that kind of increase to get a much bigger header. I wouldnt even consider an hmf since I dont think their header is really that much bigger than the pro circuit one is. just my .02 though. steve

[tinner]

T get the full benefit of the porting, you will want it to flow better. time to go shopping for a new pipe and maybe a carb.