Regarding Randy Snarr's question about shorter plugs.

If you're using the Champion REM37BY (recommended for the O-235-L2C and
others) believe it or not, they come in two different physical lengths
though they have identical part numbers!

Last time I bought a set, I couldn't figure out why I had some cowl
interference on some top plugs where there had been none with my old plugs.
Several beers later (let's face it this sort of thing would drive a preacher
to drink) with the plugs laying on the bench, I noticed that I had four
plugs that were about 3/8 inch shorter than the other four (put another way,
I had four plugs about 3/8 inch longer than the other four).

Figuring that I had merely gotten four wrong plugs from the supplier I
checked the part numbers. They were all identical with no other identifying
marks!

You may be able to use this plug (I think it's OK for a number of engines)
just be sure to get your supplier to pick out the short ones (if you can
convince him that there really are two different lengths with the same part
no.).

Dan Schaefer