I'm thinking about buying a boat with a cracked 350 block. My question is can I use a standard 350 Chevy block and transfer the other parts to it?
first, need to identify the year. you want a replacement block from the same vintage. things like crank mounting, head accessory holes, intake, etc all depend on specific vintage of motor and casting numbers.
so when you say "standard 350" remember, there is nothing "standard" when you consider that the SBC engines have been changed every few years since their inception back in 1954 to today and the mix of parts that go into an engine assembly change for its intended use.
then, the things that separate a marine long block from a truck long block are that a marine motor uses brass or stainless core plugs and a stainless cored head gasket. the cam is marine specific, however very close to a truck cam. block, heads, rotating assembly, are all exactly the same. flywheel is a manual transmission flywheel, and damper is what ever was being put in trucks for that year.
all the dressing on the motor - circulating pump, front accessory drive, rotating electrics (starter/alternator) induction system and ignition system are marine specific
if the block is cracked, the marine exhaust manifolds are also cracked.