Boy, those Zenith Carbs are pretty good carbs and for a stock engine, would be hard to beat. I have never thought that a single Holly Weber 5200 (32/36 Weber licensed to Holly in the 70s) was sufficient to feed a 235 chevy, let alone a larger GMC motor. The primary seems just a little too small. Now, using a pair of them, that is a different story and a pair of them run pretty well (I have run them on both 235 motors and 261 motors.) The thing is that a lot of folks want to move to a 32.36 progressive carb because they cant get the stock carb, whatever that may be, to run right. And its almost always the case that the poor running state of affairs remained after a home done basement carb rebuild.
I have said this for a while now and I stick to my guns on this. These carbs are now really old and in many cases just plain used up. They need more then just a soak in carb cleaner and a carb kit installed. Some of them have badly worn or seating throttle blades, worn throttle shafts, deformed ball seats, clogged internal passages that need to have a plug or two removed to access for cleaning and checking. The professional builders have so much more available to them, ultrasonic cleaners and chromate baths, all the tools to create new seats for the check balls, replacement plugs so access the hard to reach places, all the proper specifications for adjustment, wet and/or dry flow benches.
You might consider getting that Zenith of yours to someone (like Larry Isgro in New York) who knows what they are doing with an old worn out carb and have the carb rebuilt by a professional and see if that does not do the trick. I love the 32/36 carbs, as well as the Weber 38/38 carbs but even I don't think I would use one on a stock motor over a Zenith, or a Rochester or carter for that matter.
Last edited by Dragsix; 08/28/2018 3:22 PM.
