Need belt for Emerson attic/whole house fan...

I am looking for the fan or motor belt for the Dayton motor
that runs my Emerson Electric (whole house) fan.

I'm hoping someone can tell me where to look for the belt online...

Here is some information about the motor:

BELT MARKINGS:: 1230 5000 00

Dayton Split Phase A.C. motor
Model 6K 20A
HP 1/2
R.P.M. 1725/1140
Mtr Ref: 5A63 CXEKM-5114


Here is some information about the whole house fan.
I'm guessing that it may be as old as the house (up to 35 years old).

Emerson Electric
Cat. 224-D-2
V 115 A 9.7/6.6
Frame: 567
Brgs: SLEEVE
Code A
Ins class (either 8 or B, couldn't read it) PH 1.