I tested compression last night on a cold engine (155 psi top and 140 psi front cylinders). Will compression increase or decrease with a warm engine? Is the difference in pressures significant? What is recommended minimum pressure?

Also, the top cylinder spark plug wiggles more than it should. Back it out 1/4 turn and the tip moves almost 1/8". The front cylinder wigles a tight 1/16" and is more what i am used to. This plug was also loose. I assume it vibrated loose? Did vibration cause the excess wear? Is there something that can be done to fill the void like plumbers pipe dope or teflon tape?

Thanks again.

I don't know about hot/cold compression tests, but most people do tests wet and dry (with and without oil). This will tell you how much ring wear you have.

If loose spark plugs are really a problem, you could probably use a helicoil or thread replacement type device. The use of a non-conducting tape is not advised, as the thread is used to ground the spark plug, and you have a chance that the tape (not saying you can't thread tape properly) will come off and then fall intothe combustion area.

You definitely don't want an engine to have loose plugs. That will make it run wildly hot. Used heads aren't very expensive so instead of trying to repair one or both, if it were mine I'd buy two used top heads (make sure you buy the correct type H or L) and a Tyga conversion hose and be done with it.