Backfiring T6

My 1946 T6 was dlivered today and I have been cleaning (and playing) with it.

Although it crank starts on the first try and runs smooth at all speeds, when I rev it up and then back off the throttle quickly it backfires.

I'm mechanically inclned but I've never worked on engines before and I'm wondering what I should look for? Timing? Govenor?

It has only run once or twice a year for the past few years so I imagine it could have something gumed up or stuck.

Is there anything to adjust in the govenor or do they wear out? I've seen ads for new ones that claim to respond better. Is this true or a worth while investment?

Thanks in advance, Jeff

Reason for the backfiring is the distributor is not equipped with a vacuum advance (provided on later engines to prevent backfiring). So long as the motor starts and runs well otherwise, I wouldn't worry about it.