Then, you are going to have to come up with a regular nut that will fit on that shaft. You might call the man. of the engine to see if a regular prop nut is available. Or, if you really want it to look nice, then you could get an aluminum spinner. The adapter you'd have to get for it will have a prop nut built in. Hope this helps some. The safety nuts are nice, and make switching props a breeze. However, as RCKen pointed out, it would be in no way scale for the P51.