My stock 283 had 3.55 now 3.7 gears. It takes off better but could use 4.11 with the 4 spd Muncie it has in it. I think the double pumper carb may be a bit to much (Gas). My Vac sec 600 hlly works better than the 650 edlbk that it had before. Need to figure what tires you will run and what the max rpm is you want to cruise at, then select the gears.