while troubleshooting my 50+ year old boiler.....

turns out I have a clogged chimney. The spill switch trigged and I took a match and confirmed I have a clogged chimney. So I'm off to buy some brushes and rods...but while at it, my boiler is 50+ years old.

I don't use the boiler that MUCH these days as we have installed splitless HVAC throughout the house and we now have *zoned* heating.

Attached is a pic of my 50-60 year dinosaur.
Should I just wait till it totally conks out or is it due time.
Not sure about efficiency, etc....

It is time to retire that dinosaur. The efficiency is probably in the 50% range. I would not go very high efficiency if it is not your primary heat source. Maybe an 85 - 88% efficient cast iron boiler. The key to maximize fuel savings is properly size the new boiler. Heat loss not connected load. The amount and type of radiation has no bearing on the size of the new boiler.