So on IWOYTD it became obvious that a 610T is NOT the radio for B3 trucks. So what IS the right radio? The instructions that come with a 610T clearly show a PH truck of the B3/4 series for installation. So does a 610T go in a B4 only? Jeff's 52 B3 has the same cutout FEF does.
pictures below:
http://p15-d24.com/topic/38569-4th-annual-international-work-on-your-truck-day/?p=405821
so meanwhile I have a working restored 610T that I have no place for...