Magnum starfire BBC
 

Hallo, i have a quastion about my magnum ! I have bought today 2 fresh reabuild 502 hp 500 cab Engines ! Witsch Prop. I Need for this 2 Engines ? I have right now 23 Mirage on my to trs drives ! How fast will it go whis this Engines ?
Thanx a Lot my magnum Friends !
Geräts from danmark

I would suggest a set of 27" Mirage if the motors are making 500 hp, then if that is too small (too many rpms) a set of 29" Mirage props. My father had a 27' Magnum, we ran 27" Mirages, and you have 30-50 more hp than he did. Or if the rpms aren't that far off get the 27"'s blueprinted with added cup. My $.02 opinion for the day, based on experience.

I bought the 27" Mirages many years ago new for my father, then sent the props to Murphy's Prop shop in Virginia Beach (area) for labbing/blueprinting (added cup, leading edge thinned)

PS How fast will it go? Another OSO member has a 27' Starfire with 502/500 carb motors, TRS drives, and his runs 85 mph. If you spin those 27" Mirage props 5300+/- rpm you too will run 84-86 mph, fact not fiction. I would go with the 27" Mirages, I am confident that would be your best prop selection unless you want to spend some big coin of a set of custom props from Herring or someone else.

Thanx for the Info !!! How fast will it go with this setup ??

84 - 86 mph with the 27" Mirages at 5200-5300 rpm

If you really have you sh*t together, blue printed bottom, raise the X-dimensions (the Magnum picture above has the X-dimension raised to the rub rail), blue printed matched props from BBlades, I would estimate 87-88, but that is only speculation.