3.8 swap

I have a 94 Bonniville with 200K miles. The body is in great shape and the engine is still strong, but I'd like to start looking for a new engine. I would like to put a series II in it but I don't know if the wiring harness will match up. A mechanic at the dealership said the bell housing should be the same but was unsure about the harness. I called GM but they won't tell me because of liability issues. Yeah, yeah. I was wondering if anyone has tried it. Or if maybe someone might own both and could look. Any help would be appreciated.

Thanks in advance.