well rich it sounds like you have the situation under control but just a few tips from me i live in virginia so i must winterize but somthing you might try is a little drop light in the engine room when expecting cold weather or just winterize anyways. i have had a cracked manifold on my 360 for a year now and kept running but funds are good now so i will buy a new one cheapest so far has been 361.00 i dont like patching things up as far as freeze plugs go i once had a chris craft with an old 485 mercrusier in her which is half of a 460 ford block,that blew freeze plugs and heat exchanger, i bought it like that and put plugs back in it and replaced caps on the heat exchanger was able to run for a year until the head had to be machined the block never did crack. lol goodluck with your project and i agree with your friend 318s and 360s are like caterpillar diesiels of the marine gas world lol