I am restoring a 1966/67 Rayson Craft V-Drive Flat bottom boat. The engine in it is a big block case number 3855961. I am trying to figure out if this a 396 or 427. I was told it is the original motor, There are no other marking or stamping on the block other than Hi Perf and the case number on the back near the bellhousing and a K where date casting should be on the side of the block. I can tell you it has 215 closed chamber heads, hi-dome pistons and the cylinder bore is about 4 1/4 inches now, it has been freshened about 1992 but I have no info the that.