OK My wife has given me the go ahead to get new tires. For background, I have a 83 K30 cut down to 114" wheelbase, D60 14ff and detroit with 4.11 gears. I am currently on 13/36/16 TSL's that are worn out. I am tired of bouncing down the road so I am looking into the Goodyear MTR. I would like to go the 40's but I can't do the gears yet so my question is should I go with the 40's or the 37's?