355 with bowtie heads??? not enough power!

[jasonsnova]

i have a 71 nova with a 355,trw flat top pistons(10.25 comp) gm angle plug bowtie heads(cast ironversions), victor jr bowtie intake holly hp 750, msd ignition, and a solid lifter cam i forget exact specs but but i know lift is .528 int, .536 ex and has 1.6 rockers on the intakes and 1.5 on the exhasts, now problem is for as much as this is i really dont think it goes that great, it gets into the very high 12's in the qtr with a 4200 stall converter and th350 with a tranny brake and 410 gears, now im thinking about changeing things all the way around on the car. it get horable gas mileage honest 2-4 mpg, so i'm thinking tko 600 for a tranny and holley comander tbi injection , and recaming it , so i guess my question is anyone got any good suggestions i was thinking it maybe has too much cam?? i want to make it more drivable right now it just sits...kind of a waste! so anyone have something simular that works better ?? i really think this motor should be makeing way more hp/torq than it does....i'm open to suggestions ! thanks and a pic of what i'm dealing with