Hey fellows, I have a 1988 Evinrude 70 hp with a 13x17 prop off a 1978 Evinrude 70hp.The boat is a 1978 Tidecraft 16 foot "about" ,My question is, when im at WOT the rpms seem to be high, but not enuff prop, it feels like it could go faster by the sound of rpms. which prop would i need to go up...