I'm not sure this will solve all your problems. You stated that your 3 speed is not high enough. Unless this trans is an overdrive it will not change your final ratio which will still be 1:1. Fred
1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes 1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes 2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans 1947 Willys CJ2A w/F-Head engine