First, going over the chassis tube allowed a very straight exit form the heads in the first ten inches. This really helps to build power from what I have heard.



The straight length does help the power but in my case
I didnt need to go over the chassis. You try to get
1 cylinder volume before it hits the first bend (try....
thats from the valve to the bend)) but thats not
always the case, heres the last set I built for
my W-9(405ci)