I have a 250 on my 228. Claimed top speed is 47, I've hit 45 WOT. I feel like a gulfstream wants more oompf, I mostly see them with twins, either 2x 150 or 2x 200.
When my boat is loaded up with gas, extra gas in 4 jugs, ice, and 3 people for tuna, it struggles to get on plane. It gets there...