OK, after speekin to him for about 45 min., about the only thing he could come up with, without acually seeing or hearing it, is maybe try a colder sparkplug. I personally couldn't tell if thats good or not but he has been a good friend and fellow wheeler for many years. Good luck.

Awesome guys, thanks for all the tips.  I've had a good inspection, talked to a lot of people in the know and my problems are a combination of things... timing, spark, vacuum, and high mileage... there's a lot to do, but luckily it's a cheap ol' zook, and I like fixin' stuff 

Colder heat range spark plugs are generally used to reduce ping in engines
that are lean and hot running, or under turbo/super charged conditions and
where poor quality or low octane fuel is available. They can also make for hard
starting in cold weather.

All that being said, you don't have poor octane fuel, LPG is easier to ignite as it
is a gas and not being injected as droplets as gasoline is and you weather for the
most part and areas of the country are not really cold so you should have no trouble
using a colder spark plug, but I also don't see how it would really help unless your
mixture is lean, and that should be corrected for best power, not side stepped with
a colder spark plug

Wild