I'm not sure if anyone has used one of these, I hadn't heard of them before yesterday. Summit has taken the basic concept of the Autolite 4100/4300 4bbl carburetors and updated it with center-hung floats, sight glasses to set fuel level, and Holley-style jets to build a 600 or 750cfm carb at a pretty friendly price point. Dad was a huge fan of Autolite carburetors. He felt they were about as simple and effective as you could make a carburetor. Of course, that simplicity also meant they were very specific to the engine they were built to sit on. Holley jets would change all that. https://www.summitracing.com/parts/sum-m08750vs
I have owned a Summit 650 vacuum secondary carburetor for a number of years. It is a great street carburetor requiring little maintenance. Not a competition carburetor. Just my opinion.
