Look to me for encouragement- it has been about 8 years since I have turned a wrench on my project. About all I have done is pile stuff on it.Maybe someday.
My 74 W200 (bought it new) had a 360, the very best thing I ever did for it was toss the stock carb,(2 bbl) merely replaced it with a Carter from a 68 Chrysler 383 also 2bbl. Ran great, plenty power, decent mileage. Of course it had 4.10s, tall tires. Towed great.
Point is, I think the 360 will have plenty of towing power, with maybe something like 3.73s.
Short wheelbase and lighter weight will have more of an effect.
Very nice truck to start with, and nice job so far on the resto.