Head pipe

[400ex28]

Would an aftermarket header do much as far as power on a stock 400ex engine? or just keep the stock and grind the welds out

[cals400ex]

the aftermarket header won't do anything drastic. even on our 10.8:1 406 motors a full system is of little benefit. i just got an x-6 because i was told how sweet they are. you will see little gains, but not much at all.