I tore down a propane 283 chevy my dad drove daily for 10 years in a 75 4x4 chevy scotsdale, 6 years with the same oil, no sludge, heads were ok, everything was ok, except the power loss and the worn out oil pump that made a rod bearing go bad. Not a great idea for pulling power, but propane used to be CHEAP, so we just pulled slow.
