Technical Flathead question

I went out to crank my '50 Ford this afternoon for the first time in a couple of months. It fired right up but immediately vomited a mixture of oil and water out of the crankcase vent tube. Am I right in assuming I have a head gasket gone bad, or could it be something else? Prior to today I haven't had any issues with the engine at all, other than having a set of rings put in it. Thanks for any advice.

 

Try a compression test or a leak-down to determine problem.

T