Smokes coming from my exhaust.

I have a ‘73 Dart Sport with an LA360 in it. Unknown engine build. I need advice on what step to take next.

The cars been sitting for almost 3 years while I was messing around with the electrical on it. At some point it started smoking while I was testing the electrical in the last 2 years. I never drove it during this time, I only started it. I was hoping it was just condensation build up burning off, but it quite a bit of liquid coming out of the exhaust pipes. Driver side seems to be a little worse. In my not at all expert opinion, it could be valve stem seals, or head a blown gasket.

I was thinking about taking the heads to get a refresh and reinstall with new gaskets and go from there. Is there any steps I can take before hand to verify what’s causing the smoke? Any advice would be appreciated.