After looking at the OP's photo of his truck, which appears to be an unrestored work truck, I don't believe he's interested in spending a boat load of money. JW 51's idea of a mild compression stroker kit (383 cu in) & a flat tappet RV cam would be a cost effective way to go, imo.
OTOH, old motorhomes with good running 454's are a dime a dozen, so to speak. Once the roofs start leaking on them, owners will practically give them away. The engines are truck engines with rotators for the valves & factory equipped oil coolers. Converting to a carb if neccesary is easy & fairly inexpensive. Only down side is getting rid of the MH after robbing all the needed parts off it.
