Join Date: Sep 2014
Location: Santa Clarita,CA
It may be an A/C drain hole, but it is not in the proper location to be from a '66 factory installation. After looking at it closer, I thought it looked too low on the tunnel, so I went out to inspect my original unit. In my San Jose built '66, the hole is indeed higher. It is not more than 2" from the top of the tunnel. I would plug it. If you were to install A/C in the car using that drain location, you would be kicking the hose constantly.
'66 GT Fastback, 302, Edelbrock Top End, Sniper EFI/Aeromotive, MSD, JBA Headers & 2.5" Exhaust, T5Z, Currie 3.55 Trac-Loc