What are Proper RPM's to run for 1978 24' SeaRay Sedanbridge

[McBoater]

Hello,
I've just purchased a 1978 24' Sedanbridge. The motor has been replaced with a 2005 Chevy 350, Edelbrock Manifolds and fresh water cooling. Alpha 1 outdrive was rebuilt. I went out the other day, ran it about 2500-2800 rpm's. This was comfortable, making about 13 knots in rolling seas, not too rough. I don't want to over do it, but I'm curious what the proper crusing rpm's should be in order to get best fuel mileage. Also, what should top speed be?
Temp was steady just below 150, oil pressure about 60 when low throttle, then about 75 when I went up to 2800 rpm's.
Does all this seem fairly normal ?
Appreciate any feedback. I'm a decent sailor, but new to motorboats and want to learn as much as possible, thought I'd try here first.
Thanks

 

[McBoater]

Thank you for welcome and info. No manual with the boat or engine, just going by the seat of my pants.... don't want to keep asking the previous owner questions. But, as they say, it's all good and a learning experience. So thanks again, I appreciate your input