RE: MVVS 28 ??
Mike,
The MVVS .28 can be set up in rear-exhaust configuration and would spin an 8.5x6 (Bolly Clubman), or a 9x5 prop at very nice RPM.
For even more speed you can go to an 8x6 from APC, Graupner, or even the MA Scimitar.
You can contact any of the official answer guys here, if you want an offer (David Moen, Pé Reivers, or myself).