I get how to route my water lines I'm just wondering what is the best size (i.d. hose) should I be running. I have a bunch of braided SS hose that came off of a boat with OT headers. It has -8 AN fitting on it and line ID seems to be a about 1/2 . Will this work with logs or do I need bigger?

You should be good with -8 lines, some even run -10 but I would not run any smaller than what you have.  As for routing, there is a diagram floating around here somewhere.  Come out of the pump(valve in line recommended) to the logs for preheat, then out of logs to front of block or where the water pump would be mounted.  Then out of the thermostat down to the snails which dump through the exhaust.  Make sure you come out of the block with the same size and qty. hose(s) as you put in to limit over pressure in the block.