Roger,

I changed over to hidden headlights in my '68 Z24 many years ago. The 'regular' core support has indents that must be cut out to provide clearance (as you know) for the grill part of the assembly to retract...I didn't switch cores. Hope you can find someone to help install. I was able to do the conversion myself but had the benefit of being the person who removed the units from the previous car.

Bill
(Dayton, OH)