Re: force prop
Mark: Early Force and Late Chrysler used the solid tapered hub prop. It was usually mounted with a large black plastic flared washer about 4 inches diameter and 1 1/2 inches thick which Chrysler called an "Anticavitation Washer." Then the tailcone went on behind it and was held on with the same type screw that holds the shift yoke in the case -- same head, same length, same amount threaded. -- same part!
Later on, Force developed the dual exhaust midleg and lower unit. Part of the exhaust vented through the hollow prop hub. Now, since it would not fit the flared hub of the hollow hub prop, the flared washer and tailcone assembly was dropped. Since it was no longer needed, the prop shaft extension that held the tailcone was removed from the manufacturing process--every machining step costs money. Similarly, Why keep two different props in manufacturing inventory when the same prop will work on both dual exhaust and single exhaust engines? --Inventory also costs money.
I have tried solid hub props in all variations--with tailcone, without--etc.
while there may be a slight difference in drag between variations and the flared hollow hub prop, it was not noticeable to me under operating conditions. I even tried a flared hollow hub prop on an older lower unit and installed a tailcone--no difference.
I do not, however, like the black flared hollow hubbed props. When I buy an engine with one, I sell the prop. Call it predjudice or gut feeling, but they just don't seem to perform as well as the older solid hub props--no actual figures that I can quote though. At least that's my take on it.
