Kind of late to the party but the LEE engines were known to beat the valves into the head and cause a traveling miss. I would've thought this would have been discovered during the cam swap when they ran the overhead though......adjustment screw threads above the jam nut should be consistent.
I'm finishing up overhauling a c15 right now the lee is next on my plate to figure out.
psi testing the cylinders are first on my list to do I may pull injectiors out and have them tested but not sure what the cost of that will be. It's still in service the miss it does seems to be when it's hot loaded and pulling a long hill