My opinion is basically mute (I've never messed with vacuum secondary carbs) I've just always read that manual trans cars should use mechanical secondary. Cary on, enjoy seeing a tune improve!
I've been using the older version of this one for years (love having the choke on a street car, but I do live in MN :lol:)
Holley 0-4779C Holley 4150 Double Pumper Carburetors | Summit Racing
Quick Fuel BR-67213 Quick Fuel Brawler Street Series Carburetors | Summit Racing (cheaper but only comes...