What's the best way to find a dead cylinder?

Infrared gun told me #4 was pumping @ambient temperature. I had drilled out a jets on a BBD which mad it pig rich on the dyno. I may have wiped the rings on my low mileage 198. It has been sitting since 2009. Driving over the road left me no time to play with it. When I came off the road it was forgotten. Now I am working on keeping my '97 Lesabre, and '05 Lesabre rolling for my 90mi a day commute. My '93 D350 is next. I need a truck to build a house.

My cylinder head had .090 taken off it. Home port job by me, finished by @Dragnmopars from Moparts not sure if he is still alive. Ran the valves set cold to the hot specs on the stock cam for extra lift and duration.