If you're flying behind an IO-470 engine variant with a rear mounted alternator, you take comfort in the fact that your pee-wee big bore Continental (an oxymoron for sure) engine does not have that front mounted coupled alternator which on occasion has been known to trash a motor after ingesting pieces of the geared coupling  

You can also take comfort in the fact that a new belt for your IO-470 can be had for about $3-$5 at AutoZone, NAPA and other national parts retailers! Below are some part numbers that worked for me.

IO-470N Alternator/Generator IPC Extract HERE

Here is another belt option found by F33 owner, Jerry S., at O'Reilly Aviation. It is listed under the MasterPro Brand PN: 7312. Jerry says: "One thing I discovered you cannot go by the size description fully, each brand is different. Some are longer than the specs, some are shorter, the MasterPro specs are longer than what was needed, but in reality is a shorter belt which raises the bottom of the belt out of the way from the fuel pump/line fitting." (as seen below in the chaffed fuel line picture)

Now, some of you may be asking that age old question - what about the paperwork? Here is the verbatim guidance published in AC23-27, Page 12:

DRIVE BELTS
APPENDIX 1 PART SUBSTITUTIONS
 

a. Alternator or Generator Belts.
 

(1) For aircraft where the manufacturer no longer sells the original alternator or generator belt, you may use a belt made by the same belt manufacturer if the original part number is known. If the original part number is not known or the belt is no longer available, you may use a belt manufactured to a known specification such as SAE J636 and the belt properly fits the application. Pay special attention to fit of the belt to the pulley and proper tension of the belt. We highly recommend the use of technical information from similar aircraft.

(2) The SAE J636 specification covers standard dimensions, tolerances, and methods of measurement of V-belts and pulleys for automotive V-belt drives. The V -belts that Piper supplies for the PA28-140 conform to this specification.
 

Approval: This is a minor alteration and you may document it by a logbook entry. The logbook entry must reference the original (if available) and replacement belts' specification and manufacturer's identification.

Essentially, in a nutshell, your A&P/IA has been given the authority by the FAA to approve for service any part he/she feels is airworthy. Whether this be a used "serviceable" gear motor, flap motor, fastener, etc. They have the authority to make that call. Now, as to whether your mechanic will choose to EXERCISE that authority is another matter entirely. Still stuck? Maybe showing your A&P the AC23-27 guidance on belts can unstick him????

I have always believed that aircraft mechanics should be chosen as you would choose a doctor, lawyer, accountant or any other professional in whom you place great trust with your affairs. You, the owner/PIC, are the final authority as to the airworthiness of your aircraft.

It doesn't have to cost a lot to properly care for and maintain your Beechcraft!