Good grear ratio for AT setup

Hey guys looking to do a wheel swap. I’m running on the 145mm bergmeisters and want to swap over to some 7" to get a bit more clearance. Boards a 10s5, 2 190kv 6374’s, 15/60t, 4:1 gear ratio at the moment, but I’m after a bit more top end, thinking about swapping to a 15-48/50 making it a 3.21 ratio (with the 7" wheels) . How much will this affect my torque in real life? I weigh 75kg and want to have enough zip to play on the hills/dirt tracks. Cheers guys