"Belching" L-134

my flattie is belching... i don't quite know how else to describe it... it's not as strong or loud as a backfire, just kind of a burping noise coming from the tailpipe. It still seems to run strong aside from that. No stalling or anything like that. The belching starts after it has warmed up for about 5 mins and then increases steadily

It first started doing this last fall after a day of serious mudding... i had to rebuild the carb after that day because some mud had gotten into it and caused it to leak. i also pushed the old flathead very hard that day through one particular mudhole that took me a very long time to get out of so i may have overheated the engine

could mud have gotten past the carb into the intake and be the culprit? or do you think it was the overheating and maybe i blew the head gasket? ( i dont have any functioning gauges at this time... it's on the to-do list)
i don't appear to be losing coolant although i don't drive the flattie enough to be 100% sure.

anyone else ever had this symptom before?

 

Burned exhaust valve maybe? Do a compression check.

 

I'll second the valve.
I thought you were building some insane caddy block fot the flattie??
Donnie

 

Valve, or, could the timing be off?

 

still toying with the idea but i might save the CAD BB for a rat rod.... gonna do the D44's and the Saggy swap for starters.

i'll check the compression and timing on the flattie. thanks for the advice guys