Are you sure the compression gauge used was accurate? With over 40 psi difference from highest to lowest. Would think it would run rough?

 

I thought that was strange too. I did the check on those cylinders twice. I'm certain I had it screwed in far enough that the oring on the tester sealed but stranger things happen I guess. Like I said before the only thing I didn't do was hold the throttle wide open when cranking.

 

I would go find a set of rebuilt heads, don't have to be new thicker casting just get rebuilt ones. At this point anything is better than nothing at all. Leave it and it will only get worse and more costly to fix.