[911st]

My guess is the Fuel Quality Switch was cranked up with the new header install. ???

Any decent 1 5/8's or 1 3/4's header should out preform a 1.5" SSI to about 10hp assunming a same muffler.

A better comparison would be the Euro George 1 5/8 or 1 3/4" headers w Phase 9's or
Flowmaster. I believe that seems to be the standard unless one wants to step up to some very expensive stepped headers.

Not sure how much scavenging that can be done with a stock low overlap cam (tube volume and length). I think it is more about increasing efficiency / reducing back pressure.

Still, love the long tube design, collectors, and expantion chamber. Nice work.

Again, I am not an expert just what I belive.