A stock 340 cam works from 1000-5000 rpm, every step up from that is gonna gain like 10-15 hp and move the powerband up a few hundred rpm eg. 1200-5200 1400-5400 etc.. the further you move the powerband off idle the more your gonna need to step up rear gear and stall in similar fashion . above 5000 rpm isn't too useful on the street especially with 3.55 or higher. So you could go with stock 340 cam or a step or two in cam level. Stock I think is like 205-210 @ .050"
