eBay. Search for WOUND GOLD BALLS. Mostly DT 90s come up going for 10 to 25 dollars per box. Forget Balata! Way too expensive!! I still play DT 90s.

Does anybody remember the names of liquid center balata and the rubber centered balata balls from Ttitleist?

They were the Tour 90 balls. Balata covered, wound with a liquid center. I tried them in the late 1980s--along with the Tour 100--but I wasn't good enough to play them. I had a habit of miss-hitting them, causing the usual "smiley face" cut on the cover. I have one Tour 90 left that I'm saving just because it's cool.

Most of the internet marketers are going to post on Amazon or e-Bay.  Finding a pro shop iwth a couple of boxes will be hard to do, and if they do, they likely have them in a display cabinet already.  You can probably network through the Hickory Golf Association.  There are some vendors of hickory clubs that may have suggestions as well.  I suspect the HGA may have rules on tournaments about the use of modern balls.  If they do, there may be a specialty maker of qualifying balls.

I thought the Titleist Professional was also a  wound ball.  It was my ball of choice until the ProV's came out.