Okay! At peak, the 4/7 swap made .9hp, that's nine tenths of one horsepower, on an 800hp test engine. So that is just barely over one tenth of one percent. The average was up about 2.4 hp, so, .25%. Surely worth a custom $500 cam, and tearing down your engine for.
Well, maybe not.
Edit: the firing order change also changed cylinder to cylinder distribution......made it worse. One cylinder went way lean compared to standard.
