Listen to these guys. They are not steering you wrong. You're heading in the right direction with your top end, but you can't expect to win races while hanging on to your 3.07 gears - unless you have MAJOR torque under the hood, which is way beyond a streetable engine. If you are keeping the 3.07's for MPG, they could be costing you MPG, because the engine must be lugging at low RPM trying to turn those 36's. My recommendations, take 'em or leave 'em, put your top end on a 400 short block, TH350 auto, and 3.73 or 4.11 gears depending on the amount of torque you end up with. If the mud is shallow where you race, go to 34 x 9.5 swampers. Yeah, they're skinny and ugly, but they work. This would make your truck competitive at most places I race. Give us the rules you have to meet and we could get more specific.
'84 K20 driver
<font color=orange>'79 K10 mud racer</font color=orange>
'48 CJ-2A trail Jeep