FYI - Have a 1976 Nova Wellcraft (21' - cuddy at 3750 lbs) with Ford 302 (188 hp). Could not clear 3500 rpm with 15-square prop (came down from 15 x 17). Covered everything else (tune-up,clean fuel lines, water separator, secondaries wide open, etc,), but no 3800 - 4200 rpm. Getting 39 mph @ 3500 rpm. Wanted more. Two possibilities came to mind: engine starved for air and/or tight engine compartment temps were causing vapor lock. Moved fuel lines away from manifolds and block, insulated them and triple-vented stern settee base. Results: 4000 rpm and 44 mph. Concluded this solution after running wide open with no engine compartment confinements. And just slightly more engine noise. Hope this helps someone out.
