Thanks all for your input! It came off with a good amount of leverage clockwise. If some other person is doing this job and pulls up this thread later, I'll leave what I found:
For 1987 Raleigh Technium 440:
Fixed cup: Left hand thread and 24 TPI
Adjustable cup: Right hand thread and 24 TPI
Should be able to use a normal modern bottom bracket with no problem then

It sounds like Raleigh made a few with 26 TPI bottom brackets but this wasn't one of them.