Those carbs came off of Mike Swanns old PSCA heads up car, they where modded by some shop down south in SO CA, probally C&J engr.
I had loaned one them out to a local bracket racer and I didn't think to check to see if they jet extensions on them, they didn't, and that made it bog off the line a tiny bit but it ran more MPH and quicker ET than his 950 HP did at Woodburn on back to back runs
Mike didn't seem to like them back then due to the annular boosters according to him