Spent me nights & weekends wrenchin' on Chevy's and Yota' motors. Just a stock motor will set ya back 3500 "new" from Ford... cheaper way to go and add some Torque would be "freshin" it up yourself. New cam, lifters, pistons, rings and such will be at least 1500 plus your time. Lots to choose from for 351's and such, shop around. If ya' get into deckin' the heads, line boring the block and honing the cylinders or punchin' 'em out you're gonna drop some coin at the machine shop ( 300 at least ) I'd figure.
Would recommend shopping the parts before you decide which way to go, real easy to do through Summit or Jeg's and such. I re-built a stock 350 (Chevy) for 900 using stock heads and such. The Yota motor set me back 1400, never would do that again!!
Just remember, you can shoot the farm quickly re-building something, meaning drop a bunch of cash, decide what ya' want and need first... Making horsepower costs money!!
Found through the years you can get a donor truck or car pretty easily and cheap. People get in accidents all the time, pick one up for 2000 and you're back in business. Hope this helps, take care and good luck!!!payup