66 Dart GT HT Whatsitgonnabe?

Looked through the bits and pieces for the car I have in little boxes trying to find a part for a fellow swede-moparian. Guess what I found? The distributor hold-down clamp! Yay! I didn't think I had one.

Started looking for the bolt to secure it but didn't find one so I ended up sorting all the nuts and bolts. Metric, imperial and self-tapping all mixed up in a big pile. Lots of fun. Didn't find one that fits, though. I think it's a 3/8 UNF of some kind. Anyone know?