Velocity creates vacuum , I work a lot with pressurized air boxes on normally aspirated motors. they have a lot of vacuum and we get frost built up on the throat of the carb. Bigger is not always better.

Are you talking about a pressurized box surrounding the carb? That wouldn't be NA right? Not quite sure what you mean.

Yes, Pressurized through a scoop of forced speed intake

So you are saying the frost is caused by high vacuum?

High Velocity/Speed and pressure chill the air. Just like the air chuck gets real cold under volume of air rushing out

Fuel coolers :D

So the high velocity of air in the intake is what causes the carb to frost up? Hmm. So why doesn't this happen on a efi manifold at the throttle body?

water mister in the air box. LOL.

or possibly IR's with injectors over the trumphets ?

I know the temp drop in a carb is due to the venturi effect as well as the fuel evaporation (but mostly venturi effect as the air pressure drops)

Anyway, it would be nice to try some 850s or 950s but I think what I will do is get the jetting dialed in and check the vacuum under the carb at wot. If over 1 inch, I think I'll want to try a bigger one.

Thanks for the input

Apollards 461 with 496 exhaust, ovals, and vic jr oval intake with 850cfm marine holley with almost identical camshaft pulls exactly 2" at WOT.