Just looking at the options to make a boat comply with the Round Britain Class's.
Boat weighs approx' 2700kg's but is too big on engine capacity. Changing to small blocks would save 140kg's in weight. Only other option is to convert to diesel's but that would be very expensive.
I went the other way with a 22' boat 350-450mag its is very straight forward, the only thing to check out is the bolt pattern on the output shaft donut as this differs as generations of engines changed.
The bellhousing and engine mounts should be a straight swap
thats right Mr Turnip1, he most certainly is................i dream about him at night, cant concentrate at work & have even been known to call out his name when reaching a point of extacy whilst shaggin the mrs!