85 Scarab II Stock 375 hp 454's trs drives 1.5 ratio....Currently running 23p Mirages ....getting 55 mph on stock speedo....@ 4300 rpms.... I put a set of 23p Cleavers on it and got 60 mph and 4600 rpms ....My question is can i get more rpms and how much rpms is to much....