I found brass 1/2" NPT to AN fittings for my 261s (10 years and 20 years ago).

I'll look for contemporary sources and post info here.

Added/edited:

I bought from Earl's, but he might not still be around.

https://www.holley.com/brands/earls..._hose/adapters/special_purpose_adapters/

Last edited by tclederman; 01/03/2018 2:18 AM. Reason: added link