Many of the Summit-branded carbs are actually 1950-70s Ford 4bbls, not Holleys. Ford started doing the annular discharge venturis back THEN. Until recently, the only Holley-brand 4bbl with annular discharge venturis was on a drag race carb, just ONE carb. When that carb was changed-over to the annular discharge venturis, seems like people raved about it making another 20-30 horsepower on a drag race motor?
There's an Uncle Tony's Garage video where they do some back-to-back accel tests on the side of a major highway. Distance and speed. On a '72 (or there abouts) Charger 440. One of the carbs used was a Summit carb, which ran better than the others did. Which got me to wondering "Why?". Which is when I discovered the annular discharge venturis and that it was an old Ford 4100 4bbl from the 1960s or so design.
At one point in time, about the middle 1980s, Holley came out with a re-do of that old Ford design 4bbl carb. As everybody was seemingly fixated on the Holley 4160 0-1850 which most speed shops sold "cheap", that's what people bought. After a few years, the Ford/Holley 4100 was discontinued by Holley. Don't recall anything about the annular discharge venturis on them, though.
Thanks for clearing that up. Now that I read your post, I remember reading somewhere that the summit was an updated ford 4100. It seems like it has a lot in common with a holley, but the castings are split horizontally as on a Carter....
I did see that uncle Tony video, where they compare the carburetors. But reading through the comments (from Tony as well) it is clear that they knock off one of the ignition wires at some point during the test. So I don't know if that video can be considered anything but entertainment?.
Another youtuber Thunderhead289 speaks very fondly of the summit carb (ford 4100) for drive-ability as well.
The Imperial is back together now. Hopefully test drive with the new chain tomorrow.