the adapter went in from the inside with two studs that used the original AC mounting holes, with a new hole in the same place as a factory non-AC blower motor. The plate on the engine side has the same 4 hole configuration as the crappy plastic one that CAA sent and covers up the firewall hole conversion. I have a template for the conversion plate if you want me to trace it out for you. Someone here did all the endless measurements to figure out how to get the new hole in the right place and sent me one for next to nothing.