I would rather have 300hp from 7.4 liters than from 5.7. Better torque/bottom end/holeshot. same top speed,
I am used to a 5.7 in an 18 1/2', when I'm in anything larger, they feel like dogs out of the hole, the 300 hp versions the worst. good top end, but slow out of the hole
You're also boating on lakes and rivers where you can do 60 knots. Those of use on oceans and 'big water' don't need that, we can't do much more than about 35 knots, on a good day.... Most of the time, we're at about 18 to 24 knots. Having a huge engine trying to do those sorts of speeds has us dropping out of the bottom end of the power band, and then yes, staying on a set speed or on the plane would be problematic.
My 20' is in the top 10% of boat, in my area, as far as top speed goes. But the number of days a year I can open it right up can be counted on one hand. There's absolutely no point in having anything faster... Most boats around here don't get a V8 until over 25'. And then it's a small block. BBC's don't get into anything much less than about 30'
I suspect your 18-1/2' boat has a top speed of near 60 knots. What's your engine doing at 18 knots? And if you're in a boat that feels like 'a dog' out of the hole, it's over-propped.
Oh, and one more thing, the Mercruiser 6.2 has more power and torque than the Mercruiser 7.4. One of the reasons Merc dropped the 7.4 from the line-up.
Chris......
