Just got my first slant six

The one installed was a BWD RUE1, which looked the same externally as the old weathered one I removed.
OK I don't have actual measurements on that one but it crosses over to the right application. So it probably is OK. One half should be around 4-5 ohms and the other < 1 ohm. I find plenty of cases where the parts guys at the counter sell folks just any old ballast so I tend to ask. But at this point, I'd put this down on the bottom of your list of things to think about.