I would agree with Bill...with those low EGTs it does sound like its running rich...and that sudden stoppage may have been a rich bog....happens more so if you try and gun the throttle...are the needles in the stock position at the moment,
I know you have re-built the carbs...but for piece of mind I think I would check all the jets against the book,
What type of fuel pumps do you have or is it just the std pulse pump...dont suppose your fuel pump could be over-pressurising could it and causing the floats to become to high which will cause a rich mix,
Can your buddy that lent you his carbs lend you his fuel pump....a pump with a punctured diaphragm can cause odd problems inc excess fuelling...I know this from my outboard motor days...I'm talking about the impulse pump here.
