Put some diesel or ATF in the cylinders for a few days then see how well the motor spins. Pull the valve covers off to see if any of the valves are sticking when the motor is rotating. When ya drain the old oil, stick a wire or sumthin'ruther in the drain hole to gauge how much sludge might be in pan; if there's gobs of it, time to pull the pan before any damage can be done. Some folks put fresh coolant in system when firing it up; I prefer just straight H2O cuz if anything is leaking, yer not out all that antifreeze. Hard/cracked hoses are a timebomb; so are wires with loose/rotten insulation. I chased a stalling/hard start problem on my '48 & '49 for years, only to realize that the original battery cables, although intact, were full of corrosion within the sheathing material throughout their lengths, so I replaced them with new equivalent size and BAM problem solved. The vacuum chamber diaphragm on the distributor might be dry rotted, as well as the diaphragm in the fuel pump...fuel pump rebuild kits are available, distributor rebuild services are listed in the Hemmings that will replace worn/rotten/frozen parts and get them things humming like new. Local alternator/starter shops should be able to service the generator/starter as these parts were used up into the 70s on all kinds of industrial equipment. Brake & fuel lines would be better off replaced...did I mention check yer wiring?
Got a 51 Desoto with the flat 6 in it I think the car hasn't ran in 10 years or more, got it started but got an issue with it staying running when it's cold it starts right up and after 5 minutes it just dies and the warmer it gets the harder it is to get it started I think the timing is off but can't turn the distributor due to the fact it's is seized in the block was going to try a little heat it's a slow go project Posted using the Full Custom H.A.M.B. App!