Extra hp out of my 340.

Biggest problem I see here is that Glenn is going back and forth between 2 carbs and says one is more responsive than another. That instantly tells us he doesn’t have a proper fuel tune.

Glenn, gotta keep tuning these things. Preferably on a warm, high pressure day. You may be missing potential power just from your carb tune. Before you buy anything to bolt on, you have got to get your tune under control and make it rich at wot. If you’re stoichiometric or lean or too rich, you’re leaving power and efficiency behind. Best tool to tune with is an afr meter. They’re relatively cheap these days and you’re going to have to retune the carb after any bolt on anyways. So, it’ll save you time as well.

You also mentioned you have about 10k miles on this. That’s significant enough to need a good clean up of the valves from heavy coke deposits. There are many ways to do this and many products. I use water and slowly dump in a pint on a warmed up engine at about 3000rpm.