They will all work, my previous V Old School did well with a 115 Johnson and I never felt under powered, it was also very good on gas.
My current V has a 150 Yammie two stroke and if I was to repower mine I would opt for a 150 again. I have had the pleasure of running these V's with several different engine combos including a 225 Evinrude. They all have there advantage depending on what you do mostly in your boat. Power it based on your majority usage. All of them will do the other stuff within reason.
My 115 was on an Armstrong bracket and it definetly adds some perfomance but will be morte prone to balance problems with a larger motor on it. I saw that also on other V's.
With a notched transom a 150-175 would be the best all around in my opinion. Keep engine weight in mind on your search because beyond a certain point they will sit low with the thru hulls for the cockpit drains, especially if you have a few beer pounders in the back fishing.
On a bracket a 150 two stroke would be max with a good performing 115-140 two or four working well.
The two I/o's I sea trialed were nice, both had good performance, I did not care for them soley because they were not self bailing in the sense they did not drain overboard but instead drained into the bildge which I did not care for.
For performance and fuel economy I thought they were the best combination, Franco's V with the 350 was very fast he tells me, much more than the outboards he had been on and from what I hear they would be.
They of course are the original four strokes aren't they?
These hulls move out and are sea worthy but they are not built for speed, so there is definetly a point of diminishing returns. I think around 150 you start to get to the point where you have very small increases in performance after that.
If you swap out the beer bellies for some super models you will see an immediate improvement in performance, and a perpetual smile of course

I am very happy with my 4.3 litre (v6) mercruiser (chevy block) engine. Plenty of power and good on fuel. Delivers 190 h.p. at the prop.

willy, do you remember franco's top speed?

Ditto everyone with the 150 comments. I am running an 02 Yamaha 150 two stroke and fully loaded (six people, two dogs, full fuel, full cooler) hit 41 MPH WOT and cruise at 27-30 getting 3.1 MPG. With a lighter load (2 people, 2 dogs, cooler, fuel) I am seeing 43-44 MPH WOT and 28-32 MPH at 3.4-3.5 MPG.

-Svence

And that is just about as good as it gets, more HP less MPG, very little increase in performance.
I am calling Franco this morning I will ask him about the top end and MPG to.

W/the three of us aboard I doubt it could achieve it's top speed :laugh:...
Heck, too much WIND resistance if nothing else...

Called him and left message, he will call back sometime and we will find out, I believe he was in mid 40's with her though.

Just spoke with Franco, he said his 350 I/O V20 cranked over 50 mph loaded on GPS, so they definetly run with the wind for that combo

yeah thats moving pretty well.

My 86 v20 has the original 115 yamaha and it runs great. Last week i had 5 guys on it and it moved pretty well untilwaves and wind started. But she still moved great