I was going to adjust the valves on my 70 240 I bought last year.

As a matter of course I checked the compression at the same time.

The first 5 cylinders were 185 to 187 psi at a warm to touch engine.

Number 6 was 160+ and the plug was white. Number 6 is obviously

running too hot. No oil in the water or water in the oil. I did a variation

of a leak down test and air came out number 4 plug hole. It doesn't

appear to be a head gasket (or at least the typical failure), but I am

not sure what it is. The valves did not seem really screwed up.

Anyone have any ideas? I would really appreciate it.

# 6 may be lean giving you the white plug. Not uncommon for the cylinders farthest from the carbs to run leaner than the others, especially if that carb is lean already.

Cylinders 5 and 6 run the hottest in our cars. Read THIS thread at Hybridz regarding this issue.

I noticed that my #6 plug is whiter than all the others as well. Is there any way to distribute fuel more evenly to this cylinder? I suppose richening the front carb would be the shotgun method.