I have a pristine Solas Impeller from a '93 SL750. This is the smaller, 142mm pump used in '92-'93. It will not work on the '94 and later modular design pumps.

The impeller is marked 15.5 X 20 but has +1.5 etched next to the numbers. With that I would guess this prop has been re-worked a bit.

I have no set price. Make me an offer and we'll go from there.