This site store has the strut.. some are two bolts, some are four bolts, so ya need to know which. The original prop was a Michigan Wheel "Sailor" two blade and was 15X15, right hand.
EDIT: I don't see the strut on the store pages anymore, so you should call the good folks and see if they can get one
The shaft is 1" with a standard prop taper.. A new shaft coupling will be needed too
EDIT 2: four bolt Strut, Southeastern Foundries Corp, 2706 Oakland Ave, Greensborough, NC. 27403, Strut #1503, 31-34-37’ (1X1.25) HM 316700. Phone 336-299-7211