What is the difference between a curved and straight header? Also, what would be the best header selection with a 107ss Dynocam, 4.500" billet rod, wiseco piston, 3hp billet flywheel, and mikuni 22mm carb?
Curved headers work better with mufflers placed behind the seat in an area of low pressure on higher speed tracks. The length and main stage of the pipe is the most important. .990" ID pipe or there-abouts would be a good starting point for your build and it also depends somewhat on your track size (longer length helps bottom end, larger id helps top end.)