Re: What does the flair at the back of a prop do?
The prop with the plastic "Flare Washer" Is old school design dating from 1979 Chrysler. When Chrysler redesigned the lower unit to the one piece you now have, they made the midleg one inch shorter than previously. This caused many of the engines to ventilate badly. The original props had a longer hub to receive the tailcone or a separate tapered cast spacer--very nice streamlined look, but again, ventilated badly. SO: Chrysler rushed design of the "Anti-cavitation Washer"--the black plastic "Flare Washer" you have. Not great, but it does help a little. Looks nice with the tailcone too.
The other prop (rear) has a built in flare and if it is the same one as in the photo in another post, it is a through hub exhaust prop. (If not thru-hub, then it is aftermarket with the flare built in. First one like that I have seen.)
That is simply because later model Force engines came with either a single or dual exhaust lower unit. Manufacturer saved money by using a single prop design for both. You can use either prop on your earlier lower unit, although I don't really like the "semi-cleaver" design of the later Force stock prop. I don't think they work as well as the closed hub units, but if you have a dual exhaust lower, you are essentially limited to them or more expensive after market props.
