As some of you know I am the proud owner of a "Kilron Spitfire" built by the late Ron Bolton. Ron raced the K9 boat back in the seventies and was referred to as "Mad Dog". From what I have learned he built around 22 hulls primarily for "K Boat" racing so these boats are heavy It's very close in disign to a Biesemeyer and is a pleasure to drive. With a .060 over 427 big block and a 671 blower driven 15% over the boat runs 106 mph on the GPS. Not bad for that engine. Right now I couldn't ask for anything better. The problem I'm faced with is I'm going to have to change the engine block because the poor old 427 Corvette block is shot. I cant keep water out of the oil and we have had to helicoil all the studs because they where pulling out when we torqured the heads. The components in the engine are the best money can buy so I'm planning to use them over in a new Dart block. I have been thinking about going to an aluminum block so this is my question. Will the weight difference of 185lbs less using aluminum effect the way the boat handles? Right now I dont want to change anything that would effect the way the boat works and I don't want move the engine and have to drill new holes etc. I have no problem going with cast iron I just thought aluminum would be cool. Any comments would be appreciated.