Rochester carburetor Q on a '63 401

[JanZverina]

Does the original-equipment Rochester 4bbl carb for a '63 401 Riviera have a inlet on the upper passenger-side of the carb toward the rear that's for a rubber tube that's attached to a metal pipe that connects to the lower portion of the passenger-side exhaust manifold? If so, is that a preheat/choke function? I have an almost identical Rochester, but without that inlet port, that was recently overhauled. Is it a big deal if I block off the tube? I live in San Diego so low-temp starts are not typically a problem.

Thanks!   

[1965rivgs]

Yes. The reason the tube originates at the carb air horn is so that the air which is ultimately pulled thru the system and into the choke housing is FILTERED air. As long as the thru tube in the manifold is not leaking exhaust gas you should be able to eliminate the filtered air intake for now. Really, all it would take to re-establish the filtered intake is to drill a properly sized hole in the air horn and press fit the appropriately sized tube.

 

Tom Mooney

[JanZverina]

Thanks, Tom. Sounds like this was the setup on all 50-state Rivs that year and had nothing to do with the California Air Resources Board (CARB), since I see that agency was formed in 1967. Plus, my Riviera was first sold new in Washington state. I'm only the second owner.  

[1965rivgs]

18 hours ago, JanZverina said:

Thanks, Tom. Sounds like this was the setup on all 50-state Rivs that year and had nothing to do with the California Air Resources Board (CARB), since I see that agency was formed in 1967. Plus, my Riviera was first sold new in Washington state. I'm only the second owner.  

Jan,

  Although the choked period of operation directly impacts emissions I dont believe there was any legislated guideline IN 1963 which made a modification to this system necessary....yet.

  However, there definitely was a California requirement that any `66 Buick equipped with a typical V8 with automatic trans had to have a closed PVC system and an air pump (first year for this system). I dont know whether these systems were legislated directly or if basic emissions specs required manufacturers to use these systems at their own discretion. The `66 California carb was also distinct due to a provision for the air pump system plumbing and was also jetted leaner. The rare `66 Super Wildcat was exempt from the air pump system due to limited production but was required to have the closed PCV system as I believe this system was to be applied, by law, even earlier to the `64 and `65 models. So the closed breather system was already in place several years earlier than the `66 models. These emissions related changes were intended, or should I say required, on cars produced for sale and registration in the state of California

  Tom Mooney

Edited March 5, 2017 by 1965rivgs (see edit history)