1966 273 afb

All 66's had the PCV and hose to the lower part of the carb, but CAP cars also had the hose from the air filter housing to the oil filler cap. This way oil vapors get trapped in the filter instead of venting directly to the atmosphere. Later CAP cars had charcoal cannisters but they showed up in 70-72 or so.

I would just dissasemble and clean your current carb and give it a shot. As long as the engine is pretty close to stock, it will work just fine. It was designed for that applicaation. If you do convert to an Edelbrock 1406 you will need to change you air filter base as well. If you chose to take this route, I'd be glad to take the original AFB off your hands.