anyone have knowledge of zenith carburetors? which model 28 or model 228 are the "hotrod" carburetors used in multiple carb setups and how to set them up?

The basic difference between the 28 and 228
Series is in the idle system . The 28 series
has a single idle discharge plug in line with the
closed throttle plate. The idle needle valve is
located in the air intake body.
The 228 Series includes a two hole idle system
with one hole located above the closed throttle
plate and the other below the plate with the idle
needle valve located in the throttle body. I am using two matched 228 series in my GMC. Both style of carb are very similar. I can send along the Zenith service manual pdf if you would like. need a email address.

Do you know of a source for venturis? I am going to run a pair on my 175 inch 4 cylinder. They came off of a small port GMC Edmunds manifold and they may be too big. They have a 30 cast into the venturi. I guess they can be made. Any wisdom you can share about their use and tuning would be appreciated.

There used to be a place in Michigan but they have no longer got parts for the older Zenith's. As an alternate choice I have had good luck with "Carb Junky's" in Atlanta. They have a large selection of Zenith carbs and parts. They can also refer you to sources for replacement venturis. I'm far from an expert on the subject (full disclosure) but have been working with my dual setup for a few months trying to get it adjusted in. Learning as I go. Beater if you want info I have in print I can send it along via email. My email: larry@ingraphicdetail.com.

Thanks, I've got printed stuff I was looking for experience. I have had duel Zeniths in the past. It is too far in the past. I guess it will be like all carb work just take it in steps.