where could i find an OEM voltage regulator in the US?

Howdy,

The PN, from Swedish Treasures is 238640. But it listed there as "NA".

A search found this page:
http://www.oldvolvoparts.com/

which lists a phone number to call for inquiry: 714-963-3700 with no other information.

I looked up the number. Intelius reports that this is a business in Hunington Beach, California. It just might be legitimate even though their web "site" is nothing but a listing of part numbers.

You specifically asked for availability in the US but just in case, Scandcar in the Netherlands has one for €69.45:
http://volvoklassiekeronderdelen.nl/shopping/product_info.php?products_id=597

This just might be the opportune time to change to a GM SI-10 alternator. I put a 55A one on my car with a homemade bracket. Ron Kwas sells mounting brackets to mount a GM style alternator. You can get the alternator at any parts house for less money than the regulator you are looking for.

--
Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 52 year old fat man. ;-)