I kind of depends on how much room you have in your engine compartment. Check on room between the coupler and stuffing box. Also space above the top-most part of the (new) engine.
The good news is that a modern engine, like the Betamarine, is physically a little smaller than the equivalent power plant of 40 years ago. That difference was significant when we changed out the original Universal 23 hp for a new Beta 25 hp. Weighed less, also!
But then, we were never lacking HP; we just wanted to start over for not tooooo much more $ than it would have cost to overhaul and replace major parts of the total OEM drivetrain.
Perhaps unneeded advice but worth mentioning... with a new engine, you replace all the other worn out and dying parts. NEW: engine, trans, mounts, wiring harness, panel. And we upgraded the alternator size as well. Another nice 'new thing' to have: a warranty.
Full disclosure: the local Betamarine dealer is a friend of mine, and so is the ship wright that did the very skilled mods on our bed log moldings and did the actual install. I have several blog entries here with some commentary, BTW.