There are reasons most older boats are inboards. Engine cost. Repair availability. The amount of stress on an outboard transom is 10 times that of an inboard, if an outboard transom fails it can be fast and catastrophic. Inboard transoms get flexible and leak long before failure. Not many inboard transom fails on the internet but a few outboard transom fails.
A mercruiser inboard has had, for the most part, 80+ years of ironing out the bugs with the same design. The old saying, if ain't broke don't fix it. They just refined.
An inboard is essentially a car engine and most use a GM type engine. If purchasing stick with a common engine, not one designed for a boat. An inline 3.0 engine was not used in cars very long due to issues whereas since 1955 GM has basically the same designed V8's
The old legs, Alpha still I think, have issues. But the newer Bravos' are almost bulletproof. They shift differently too, the older engines needed a cutoff switch when shifting. A momentary engine cutoff to take pressure off the lower gears to make the changes. These were often an area of problems.
Newer exhaust manifolds with full fresh water closed cooling systems need almost no winterizing and don't crack as much as they used to.
I also like the lower center of gravity adding to stability and less porpoising, a draw back is sometimes the engines are placed under the deck to make more room and freeboard is farther from the water.
A leg can be re and re in 1 hour or less and engine can be done in similar time, maybe a little longer if the wiring package isn't on the engine, there are 4 bolts holding it in, hire a tow truck to come and do the lift if necessary.
A 300 hp Yamaha costs; F300. MSRP $36,611.00 - $43,628.00
5.7L Mercruiser 350 GEN+ 325 hp Marine Crate Engine - LIST PRICE: $6,607.94 TODAY'S SALE PRICE: $5,913.54
Mercruiser Bravo 2 drive - $14,507.56 Cdn But Bravo 1 and 3 both will fit.
Alpha 1 Gen 2 - $5247
Brand new inboard and stern drive around $21,000.00, outboard, $36,00.00 a difference of 15K, that's a lot of gas and enough for another brand new engine or complete rebuilds years down the road.
Inboard shifting issues and the leg gets changed, engine ditto, an outboard the whole unit needs to be worked and then the wait time for parts.
Also the inboard transom hasn't had all that stress of 300+ hp pushing on it or holding up that weight of the engine that an outboard does. The engine sits on the bottom of the hull stringers spreading out the stress of weight and propulsion. Think of how a lever works and then think of how an outboard sits of the rear transom, that's a lot of stress.
Interchangeability, costs and availability.
Outboard engines are becoming much more reliable, powerful and economic than in the past but are still unique to everything else, interchangeability issues causing added costs.
No matter how you go, just look at the number of older outboards available vs the number of older inboards.
20' cuddy cabin, 5.7 liter, bravo leg preferred but alpha for under 20K. Lots out there.
Where you going with it, how many on board, towing, storage, a little mechanically inclined?
