electric fan on a 22''champion rad

I had the same problem in my 68 Dart 340 (same radiator as you). Started with a 16 in fan pushing and it ran too hot. Tried it as a puller and nothing changed. Went to twin fans off a Jag X type pulling the air, one on a 195 sensor and the other on a switch. Always had to run the second fan to try to keep it cool at freeway speeds and it would still get too hot. Figured air flow so pulled the baffles out of the fan shroud , no luck. Made kind of a sheet metal funnel system behind the grill to channel the air though and it kind of help but still got hot. Like it has been beat to death and for a good reason... took it all off, went with a 7 blade fan, fan clutch and shroud and problem solved! Never gets over 200 even on the hottest days freeway speeds or bumper to bumper.