a Man of one word...and a smile!
Mike,
Anything can be done, of course, to Gazim's point. Question is how hard and (more likely) how much money does it take? Almost any motor will fit if you have the fabrication skills and/or money. I saw somewhere where a modern big truck (semi) motor had been stuffed in a pre-war pickup. Radiator had to go into the bed...
Having said that, you may want to search around the forum and Internet in general. You really have to decide on the end-product. You already have broken the bonds of a stock restoration. Are you going for a "period-correct" hot-rod look? Or are all bets off and you really don't care what someone thinks when they look under the hood? I think you are already in the last category...so...if you really don't have any affinity to any particular motor, you should get on eBay and Google and start pricing motors. You have to decide just how much horsepower/torque you can live with given your dollars you have for that. Don't forget that for whatever horsepower you want, you need a transmission and rear end to back it up. Price on a new stock F*rd 9 inch rear complete with disc brakes is over 2 grand with a Posi gearset.
If you are not intimidated by wiring harnesses and computers, add the modern fuel-injected motors into the mix. After several hours of searching on prices and horsepower, you will conclude what type engine you want. Then I think you will be able to ask a more specific question or questions and get some more appropriate help.
My .02...
