Just purchased a Tahiti with Berkley pump and no engine. Have a 455, gonna go through it and build a mildly unstock engine (different cam, mostly reliability upgrades nothing fancy). Probably gonna change pistons to arrive at 9.5-10:1 static compression. I got all the marine pieces, front cover, manifolds, risers, driveline, three point mount with the boat. What i did not get was a flywheel. Do I run an automatic style flexplate just for the starting ring? Or do i need to locate a manual trans type flywheel? My instinct and gut feeling says i need the heavier flywheel for proper idling and to dampen the engine.

My current engine plan is:
455 probably punched .030 to clean up block with flat top pistons
G heads (80cc chamber) large valves
polished and balanced rods
balanced rotating assembly
comp cams hydraulic cam for A impeller (most likely what it has in it will verify before cam order)+compatible springs
through hull exhaust
8-10 quart oil pan with trap doors for oil control
stock intake until i can afford something better
HEI distributor w/ MSD module w/rev limiter
bypass thermostat kit

I have an industrial relief valve that can be set to 10-50ish psi to provide a low pressure water supply to the engine.

How does the bypass thermostat work? I read on a website that the big block fords can use a a standard marine thermostat with bleed holes drilled into the plate of the thermostat. Could a bypass system on the olds engine be created by placing a restrictor into a stock style bypass line and dumping this overboard? This would create a flow of water by the thermostat as it is heated from the engine. When the water heats enough to open the thermostat more would flow and bring the temperature back down. But if plumbed the traditional way of using the manifolds as preheaters would this cause really hot water to flow into the engine from the manifolds? or is this a non issue due to the continuous flow through the bypass? I dont think I should take the manifolds out of the loop because then it seems i would then introduce really cold water to the engine when the thermostat opens as there is no preheat. My worry is if there is not enough flow through the bypass, will the manifolds overheat? On a side note boats running headers have no preheat.... So i could just plump a second line from the pump through the manifolds and cool them that way and dump into the risers. Then come off the relief valve and into the front cover inlets, and off the thermostat housing with my two lines to also go to the risers and dump engine water and somewhere plumb the bypass line in there. Am I making this more complicated than it needs to be?

One other thing, is there an ARP bolt number to fasten the PTO and flywheel to the crankshaft?

Thanks,
Eli