Bill, Best solution is rear end gears, not sure what's on the market today but 3:55 gears will really help. When I first got my '46 I swapped in a 54 passenger car torque tube rear from a powerglide car (3:55 ratio), may take some searching to find one today. This does require some mods to make it work with your springs. I also put the 216 in storage and built a 261.
Best of luck
