If you are just going for brute power and low speeds, please consider the clifford performance cam size 264. It still holds 2 world records to this day, and you get an average of 80% torque off the line. That mod with a minor manifold and upgraded carb, a slight exhaust modifcation(you can push all air you want in but if you cant get it out just as fast whats the point), also look into re-gearing, i have a 3.08 in my stock 95 EFI, it pulls like a bat at of hell. Dont even see a difference when i hit the gas. But i also do more highway with loads than hauling, i can pull roughly 8k on highway doing 65 and not be pushin more than 2.5k with od off of course. But with what you are doing, and if you are truly going to go all brute force with low speed and dont care about mileage or driving it so much in town, than go with a 4.56 ratio. My buddy has 5.12 front and rear on his truck and granted he cant go more than 80 without pushin 3k, he can beat most bone stock mustangs off the line to 50mph. But it all depends on the true application. I would go 4.53 just because it seems more practical because you will stay in the LOW rpm range on a farm with that load and not to mention with that cam mod they compliment each other as long as you stay in the low range. With the carb i would consider a 4barrel over a 2 barrel as long as you do the exhaust mod. from personal preference and experience i found clifford long tube headers to free up ALOT once i got rid of my EFI manifolds, 20hp and 26tq dyno numbers) and i also put 2.5" al way out back into 3.5" echo tips no muffler or cat, breathes like a champ but not legal in most states (noise and emissions).

If you have any questions just ask, but good luck!