This project is very interesting to me as an owner of an old tug. My 94 Centurion Falcon (owned since day one) cost me $14,500. I have redone the interior at the tune of $3,500 and added PP Zbox. I am sure that at some point soon it will need a heart transplant (still runs strong now at 2600+ hrs) and seeing what others are doing is very helpful. Currently I would stroke the 350 and upgrade intake and heads. Not sure if I would convert to EFI. I am guessing the value of my boat right around $8,000. You could get into a good older tug and upgrade as needed for I think easily under $15,000.