Welcome to the v-drive forum... now you dunnit...
You've probably got what's commonly referred to as a split-case Casale. If the mounting plate is sandwiched between the two case halves, and the halves themselves are an oval shape, then that's what you've got. If it's a square box, then it's a top-loader Casale. It's usually found in older boats and predated the split-case version. If it's got a mounting tube/shaft sticking out of each side in the direction of each stringer, then it's a C500, typically used in heavier cabin boats or 21'+ daycruisers.
If you wanted to overhaul your box, you've come to the right place- there's guys on this board that can talk you thru this stuff, Tom Bentley of Menkins is a member (he's got all the overhaul stuff, trick parts and boat-loads of brains about Casales) and we've got some data sheets and exploded views floating around here somewhere.
Any adjustments to what I said above will follow at the hands of those more knowledgeable than I.
DaveA