best single motor hp for 1983 seacraft c.c.

[ScottM]

Depends on your definition of "enough" and what you intend to use the boat for. If your carrying a lot of fuel, gear and crew, maybe twin 150 or 175 2- or 4-strokes is the way to go. Lighter loads and inshore fishing, a single 200 or 225 will do just fine.
On my dad's 23 Sceptre (3300# dry weight, 144 gal fuel), a single 225 Yamaha 2-stroke gives us a 25-26 knot cruise at 4,500 and a WOT of 35 knots at 5,400.