318 wake up or swap larger?

Hello all, im day dreaming about a little more power. I have a 1975 d100 2wd with 318 and 727 auto. The truck will be used for general running around and to haul a double snowmobile trailer once and a while. Not too concerned about milage. More info.....3.23 rear end, 31" tires on it(not my choice came with them) 2 barrel carb. I do want it as reliable as possible. Money is of course a consideration. Would like to stay under 1500 if i can. Thanks in advance
Author: 1stdodge