07-10-2003, 09:56 AM
I have an 84 comp with pcm 351. The prop is a 13x13 prop that is not cupped. Is this original? A guy I ski with has an 85 comp with a cupped prop. I notice that at 34 mph, he turns about 200 rpm less than me, (I turn about 3700). Should I change to a cupped prop, and which one? Will this help with performance and gas milage? thanks all.