383 work motor please help!!

Hi, my name in Steve, I have been reading the arcives here for about a week now and WOW, what a wealth of knowledge you guys have here! I was wondering if you fellas had any input on how I should prioritise my spending on parts and just how much bottom end im gona need? I have a 1987 chevy C-30 custom delux with a steel flatbed and duelys, it weighs just over 6,000 pounds. The trans is a four speed stick, well its actualy a three speed with a granny gear thats so low that you can get out and run around the truck while its chuging along. (to much whisky) The gears are so low that top speed is only 70-80MPH. So no high RPM screamers just pure torq! The block is a 4 bolt main #3970010 bored 0.030 over. I plan on using a stock TBI and intake. I want to ge able to work the shit out of my truck FOR MANY YEARS so I would rather error on the stronger side! Especialy in the bottom end!!!I will be finding some good used heads, any sdugestions there would be welcome as well. I will have a hot coil, good wires, clevite 77 bearings, a K&N air filter and headers. other than that it will be a budget oriented build. This truck will see a lot of heavy loads and one heavy ass foot so any spots that I should pay more attention to please let me know! Thank you in advance for your replies, and LETS KEEP 'EM SHINY SIDE UP!!!

From what it sound Like you might be better off with a Mild 454ci Low Compression BB Chevy .