Summit Racing offers similar kits with better components, such as forged pistons and double-roller timing chain. It's about $150 more...but a better value. The ebay deal says nothing about the cam included in the package...
If you must resort to such a kit for your marine application, pass on the Ebay kit and buy the Summit kit. Be sure to disassemble your engine first and determine what size pistons, bearings etc. are needed before ordering the kit.
Ideally, it would be best pass on such kits and instead custom build your engine to your specific application.
LO