We use a 10# Freon bottle that has been converted to a pressure tank. Have a 0-10# regulator on wall to cover anything with a carburetor and a 0-165# (compressor limit) regulator to cover most fuel injection units. With this set up we have almost infinite pressure settings to dial in what works best and then use that info to buy a pump/regulator. Learned the hard way about going by what the repair manuals say. IIRC 4 cam Ford engines were supposed to be at 27#'s idle and 44#'s WOT but instead need 61#'s to properly atomize the fuel mixture. Probably too exotic for a home shop but if Don used one of those 2-3#, been around forever, pot metal fuel regulators on his weed sprayer it might work pretty good. Darn sure does away with rusty tank/fuel line/rotting hoses.
