A word of caution, if that BBC engine was originally built for automotive use I personally wouldn’t install it in your jet boat. For a marine application certain internal engine clearances need to be slightly larger. Depending on the material of the pistons, cylinder wall clearance needs to be larger, I like to see an additional .001” for main and rod oil clearance, along with an additional .002-.004” for the thrust. Valve stem to guide clearance is another very important clearance that needs to be set correctly. All in all, for a marine application with an open cooling system you need to allow for certain internal components to grow due to thermal expansion while the external foundation meaning block & heads will not grow due to low temperatures. In addition, do you even know what is in that engine, and how it's set up?, example, compression ratio, cam spec's ect, ect. Plus that oil pan won’t fly, you need a marine pan like something from Dooley and a windage tray is a big plus. This may seem like a lot to digest, but looking at the big picture, if you decide to install it as is and score the cylinder walls or stick a valve in it’s guide and the piston hit’s it, these issues could be the demise of your engine really quick, do it once and do it right, you will be better off in the long run saving time and money.
