Rudi,
1667 is really 4.74" most all the way thru the blade.
H-667 is 6.92" of Trailing edge cup, it also has much less blade
area, and the blade width from the leading edge to the trailing edge is
Much less than a 1667 which is wider. The H-667 is also around 68mm
in diameter. It is a good hydro propeller if pitched up a little bit.
Thanks,
Mark Sholund