Put a Vintage a/c kit on the '66 Beau over the winter.  I worked with their tech representative, and they assembled a hybrid kit with the Pontiac Tempest/GTO "head" end (controls in dash), with the Chevelle BBC spec for everything else.  It went in pretty smoothly, the only fabrication was getting the wires from the controls to the blend box correct in length.

BUT, the old girl just WON'T cool, now.  Have put in a Cold Case high-capacity radiator with thermostatically-controlled electric fans 

1966-1967 Chevelle / Malibu Cold Case Performance Aluminum Radiator & Dual 12" Fan Kit, Big 2 Row, V8 With Manual Transmission (ecklers.com)

..and a high-flow 8-blade aluminum water pump, advertised with 35% higher capacity than the stock piece.  It's running 220F+ on country roads, at moderate (50-60 mph) speeds.  At lights, it gets scary.

I was going to send it back to the dynotuner, thinking maybe it's leaned out too much, but then, my buddy put Vintage a/c on his '66 Chevelle 300, with a carbureted 454 and a five-speed Tremec, and HIS operating temps jumped 20F, whether the a/c is on, or not.  

We're talking with the manufacturer, and suspect it's air flow restriction through their condenser that's the root of the problem, but would appreciate any thoughts the veterans on this board might have.  Mine's a mild BBC, Holley Sniper EFI, put about 220 to the rear wheels after the dyno tuning.  Not exactly a pavement ripper.  700R, turns about 2100 rpm at 60 mph, so the engine is barely loafing on a two lane cruise.  

Thanks for whatever advice you might have!