Re: 1979 Sunray??
I had a 1983 Sunray 16 1/2 foot open bow. They were made by Arivee boats in Anahiem Ca (at least mine was). They put a Chevy 4 barrel 305 OMC in the thing. They had to cut out the fiberglass in the back end to make it fit. The boat was way stern heavy as it was only designed for the V-6. I don't think the company cared about overpowering boats. I believe they are no longer in business.
Anyways, it was a fantastic boat. I could pull up three slalom skiers with ease. I had the boat 24 years and just got rid of it this year. You don't see too many Sunrays anymore. Enjoy it....