Help with carbourator that keeps flooding

[TruckintheBoro]

I'm hopeful you all can help...I have a 67 C10 with a 327 that I bought a few months ago. It needed a bit of work and so I took it to a semi-retired mechanic who still has a business working on big propane delivery trucks, but who grew up working on engines before fuel injectors, etc.

Anyway, he cleaned out the carb, installed a new float kit, installed a new choke cable, replaced the starter motor. I got the truck back and ran it for about 10 days, then one day it wouldn't start. Starter was turning, but no engine catch. Then something scary happened...starter motor was turning away and then it came to a sudden halt with a bang from the engine like someone had slammed a heavy door shut.

the mechanic came to my place and said that the carb was full of fuel, that the fuel had been pushed beyond the carb into the cylanders and into the oil. i guess the bang I heard was the sound of the engine stopping turning because the piston was hitting a cylander full of fluid?

they towed the truck back to their place (at their expense) cleaned everything up, changed the oil, and tried to find a cause, but weren't sure what happened. suspected it might be a stuck float at first, but they said that seemed ok. I then drove it for a week fine, but last night it happened again. Very frustrating and potentially very expensive. I am not a mechanic or tinkerer so any fixes or repairs I'll have to pay someone to do. Any ideas on what the problem could be?