Throttle stops brands

[Robbie Welch]

Looking to up date my old spring closed air open leakage style. Thinking about an under the carb air on air off unit. I have a couple questions,with a 2"spacer on to check clearance the hood clearance to the bowl vents look close, how much clearance do you need for them? What brand of under carb or leakage style stops is everyone using. Thanks for the help Robbie