bertram31.com

My 1980 FBC came to me with 6BTA 270 HP and 20x25 three blade props.Top end @ 2600 RPM is 28 knots.Cruise @ 2400 RPM is 25 knots.Cruise @ 200 RPM is 22 Knots.Gears are Hurth 630-A 1.56 to 1. There was a spare set of three blade 18x19 props. Hope that info helps.Must be close to what others are getting out of the same equipment.

JR

The 18x19's are a little small. I ran those with my big block. With my 270's I am running 20x23 4 blade, with some cup. My top end is 30.5 knots, don't have a tower or Hard top so that makes a difference.