Ladd,
I measured the prop hub from the resin 1/48 kit and its very close to the Allyn hub. Possibly using their hub to replace your metal cast hub might work. Here are your possible options....
1) Leave basically alone although grinding some off the blades at the spinner's junction might help appearance wise.
2) Use the old hub and modify it. Here's how I would do it...
a) measure the inside diam. (ID) hole left in the nose
b) go to the hardware store or McMaster-Carr and see if a "Pop-Rivet" would fit the ID or is slightly big.
c) If one is found, bore out the hub slightly undersized to match the actual rivet pin (not the flanged tube).
d) reverse the rivet pin so that the pin is in backwards. The knob of the pin is against the narrow opening of the rivet
e) whatever depth you bored out on the hub shaft hole, trim the pin to match or be a millimeter long.
f) wipe pin down with alcohol and cover about a third of the pin with a slow cure epoxy mix.
g) slide the hub into place. Let cure for two days. Besure not to get Epoxy in side the new "bearing".
h) trial fit that it goes into the nose's new shaft hole. Adhere if fairly tight with glue stick, no kidding.
If you ever want to exchange it, just lossen the bond with rubbing alcohol.
Replacing the blades on the old hub.... There are some mold methods that can create those same blades on metal but... the blade profile is wrong and they are very brittle. I use an ULTRACAST 1/48 P-51Hamilition Standard Cuffless assembly and it's worked out well. I just took some time to workout a pitch gauge, Dremeled and filed each blade to fit the stub and used 5-minute epoxy. Took a Saturday afternoon to do.
3) Last would be to convert totally to the resin Hub and Blades to replace the Prop Assembly using the method above to create a prop shaft.
4) Find and original unit?
The info fot the resin assembly is below...
Ultracast Ph 513-823-0181
www.ultracast.caPO Box 31025
Guelph, ON, CA
N1H 8K1
PRT# 48137, P-51 Mustang Hamilton-Std Cufless 4-Blade Prop and Spinner $10.95 ea.
Good Luck,
Tom Sanders