Cylinder head discussion 340 with stock above deck pistons

The Friday night street legal shoot out we participate in to do these 1/4 mile passes at mission raceway does NOT allow open headers or un muffled cars. It's a street car shootout where it's always heads up and people are just racing their cars and having fun. You can get 9 or 10 passes in while they are open because it's not a bracket race, just heads up to get people off the street and into a track where they can go all out safely.
Uncorking the exhaust requires another carb tune unless its tuned wrong now and you get lucky.
Many uncork the exhaust and go slower.