Re: 408 stroker build question
Your combination should be fine. One word of caution, Boats have cold water pick ups for cooling the engine , not radiators like cars. Because of this the water temps are FAR lower than a car. This keeps the block from expanding as much yet the pistons are seeing temps like normal. The piston to cylinder wall "should" be increased by an additional .001 over what the piston manufacturer recommends for car use. With nearly double your former HP , you should get to that "secret" spot quickly. 9.7 is perfect for 87 octane. Keep the timing around 32-34 "total" , no vacuum advance.
Experimental Ford parts collector.