Boat Buzz

Believe this to be a 327 Flywheel Forward, but just getting our way around it. Valve seals rotten, oil fouling plugs, but we can make it run. Compression good; vacuum very low and intermittently goes to zero causing engine shutdown. Immediately restarts. Gonna pull the heads and reseal the valves; where do we get gasket sets and torque pattern/specs for this motor?

Block casting numbers 35 GM 3970010
Will add block stamped numbers soon.