68 Dart Radiator Confusion

Hi, My first post here. I need to replace the radiator in my '68 Dart with a 225 engine. The Mopar sites I've found list the replacement radiator size as a 1.25 in. core depth and 18 5/8 in core width but mine is definitely 3.5 inches depth and 19.25 inches width. The part number on mine is 2898023. Here's an example of of a Mopar replacement
More Information for APDI/PRO 8010354

Is the 1.5 inch ok? Any hints on what to do?