Number Dummy, I'd like to answer the question you asked the original poster of this. Would I still want a unibody? Hell yes, they look awesome and since I'm an F250 person, the more awesome. I would simply add seat belts. I think everyone is so overhyped on disc brakes. Drums worked fine for 70 years and are still on heavy duty trucks. The only one I will change to disc is my '69 F250 because they were a stock option and a 100% bolt on with parts from my local NAPA store. I just left the truck driving business after 37 years and straight axles never bothered me (if the road is THAT bad, then I won't drive on it, lol) and whether they are hydraulic or air brakes, drums stop fine. Years ago I was into the engine swap thing but thats often a royal pain. The idea of putting an 8 mile per gallon big block 460 in an older truck makes no sense but I do understand personal desires and respect it. I just hate to see so many old vehicles routinely butchered as they are now.
as for engines I always liked the y block v8 this engine will out last most engines today extra thick heads and block good oiling engine,good milesper gallon,alot of parts out there,still have my truck that dad gave me for my 16th birthday back in 81, 1959 f 100 custom cab short bed,yblock 292 3 spd on the tree with od,i put thunderbird 4 bbl carb and duel exhaust ,stock,there wasn't a stock 59 chevy pickup that could keep up with me,once dropped in od 100 was nothing to do,enjoy I always prefer to try to restore them back to original takes time but well worth it,
the Y block is one of a kind. Im all positive about them except the rear mount distributor which means laying on top of the engine to get to it (unless you have a 57-59 Ford car in which the hood opens from the rear)