If you want better cooling for your big-block Mopar, a wider 26-inch radiator core support is recommended. Here's how you attack the surgery!
26 inch Radiator Support Replacement (68 B Body) - Moparts Forums
Upgrade Your Mopar's Core Support to 26 Inches & Get Cooled!
Upper Radiator Support - 69 Dodge Plymouth B-Body (modify for 70 models) Radiator Support
1966 - 1969 Mopar B-Body Radiator Upgrade - US Radiator
1966-1969 26 Core, V8 Mopar Applications Aluminum Radiator
Wizard Cooling Inc #1640-200 1966-1969 26 Core, V8 Mopar Applications Aluminum Radiator
Mopar 5202 8760, Engine Cooling Fan Clutch : Automotive
Changing radiator support from 22 to 26
Mopars Need Extra Help With The Heat—Here's How To Fix It!
1966 - 1969 Mopar B-Body Radiator Upgrade - US Radiator