Timing, valve lash, fuel mixture, but mostly another 600 rpm. Trying to get this Super Victor to work. This is the first time I've had so much intake for an engine that adding the 2" Super Sucker didn't help. With or without it the two curves look exactly the same.
Have been running with the $136 Summit 1-5/8 headers and will now switch to TTI 1-5/8 to 1-3/4 step headers.