I put a 22" cold case in my 70 duster and tried putting a mech fan/clutch in. Would not fit at all (hit the core). Pulled the rad and went 26" 3 core champion. Worked great with contour fans.
When they sent me the measurements I was surprised. I've seen a few people run them so there has to be a way, but nothing I'd want to run would fit with one of those.