v4 75HP question/ give it a pass
Your V4 weighs an awful lot for a 13 ft boat (C-D version of the Mad-Cap is 13' ). Finding high pitch OMC props will be difficult. There is no point in spending $$$$ opening up the intake side of any 2 cycle engine without opening up the exhaust side. A better route to go would be to find a Merc KG9 tower & gearcase, put a 44 cube powerhead on it(a bolt-on). That combo would probably be 75 lbs less than your V4 for starters. The Merc can turn higher RPMs out of the box, no intake work necessary and you can still find relatively cheap high pitch props for the KG9, they show up on Ebay fairly often. The props will be brass 2 blades and you should be able to get them re-pitched without too much trouble. IMHO