gasket kit

Most will be the same for Auto and Marine. If they are exposed to water and use a steel core they are upgraded to stainless steel core.
The upgrade to the head gaskets is more complex. The fire ring around each cylinder is made from a high grade stainless which is 3 times more resistant to detonation damage than the Automotive fire ring. They also change the main body of the gasket core to stainless again to improve the ability to resist rust out.
I use the Marine head gasket if building a performance Automotive engine just to have the detonation resistance and not have the cost of a full Performance head gasket. Boat engines work hard and the fuel bought on the lakes and rivers is not always the best so the head gasket upgrade is worth it.
The Marine gasket set should include the various Marine specific thermostat gaskets, you might want to check on that part.