Converting airplane engine to airboat engine spark plug questions?

Question

in the making of a small airboat is there a recomendation of cheap auto type plug to use on a continental O-200 that would call for an REM40E in an aircraft. any ideas would be helpfull I cant come up with a good idea after going through books and data on the net how to get the right heat range mostly is the big issue.

Answer 1

Actually, you can get an adapter from aircraft spruce and specialty that will let you put in a auto spark plug in an airplane engine.

Answer 2

Sorry to say there is no replacement and you will have to purchase the real spark plug.  I assume you are removing the engine data plate and returning it to the manufacture as a liability issue down the road.  If not its something to consider.

Answer 3

I would try different automotive plugs until you get the best results.  It might be time consuming, but still cheaper than $20+ each for an REM40E.  

I had a friend with a homebuilt Taylorcraft that used automotive plugs in an O-200, but I can't remember what they were.