Alternate fuels in old iron can
be done. An LPG powered 1964 Buick Wildcat
This is from a Wildcat owner is the Netherlands (edited for clarity):
"[I've got an] Impco model E regulator and 300 mixer. The mixer sits in the air cleaner. I'm running mine for 7 years now on lpg, it has only one carb. I have hardened valve seats in it and a higher compression (about 12:1) and the engine is always hotter then usual. I also have a re-curved distributor in it and run now about 14 degrees BTDC. I have a 120 liter gas tank and all brass (copper) 8mm lines. Yes it burns the [valve] seats. Maybe not now but over 65 miles it does."