Yes, 165 refers to HP. Some of the Mercruiser sixes had a Rochester 2-barrel carb on a special intake manifold, I believe. If that one's available, definitely use it. The crankshaft should accept a normal flywheel or flex plate, so bolting up a transmission won't be a problem. The exhaust for the Mercruiser is water-cooled so it will need to be swapped for a non-marine manifold. Using a block casting number to identify a 230/250 doesn't work, as the same block casting was used for both engines. Measuring the stroke is the only sure way to tell the difference.
Jerry
