Its saturday night - i'm stuffed!
Well... all went well! The engine has a new impeller, a new exhaust, and lots of other little things done. All the coolant (river water) hoses are hooked up, going in this order:
River -> Water-cooled Sump -> Filter -> Water pump -> Water cooled Exhaust -> In Engine at timing end -> Out the head at the flywheel end -> Out the exhaust
I ended up making the exhaust from copper plumbing pipe, soldered together with a propane torch. Should do the job for a while until i can afford something proper.
I also plugged up that pesky hole in the head! Ended up just using sealant, a big bolt, and a hammer.
I hope you're not all getting the impression this is being held together with sticky tape!!!
Its looking sweet now i've cleaned all the tools out of the boat and given it a cleanup...
Still to go: set the timing, finish the exhaust, and modifying the engine cover. Possibly get a 350 holley and manifold to match. And take it to the river!!!