[72SB]

Mark

Are you looking for more power, fuel efficiency or feel you have a pump issue?

IMHO it's best to remove carb and just do it on bench unless it's just metering rods and step up springs. Bending over fender and changing small parts inside carb....you don't want to drop anything inside it while on the motor.

My go to carb for SBC and SBF is the 1406. Edelbrock makes a specific kit, # 1487, specific to the 1406 carb. It has a variety of jets, metering rods and step up springs and a grid indicating what combo of each to make changes. My need was when I went from a stock 327 to a head/cam 355 crate motor making over 400hp.

You really need to have timing nailed before making internal carb changes. Controlling vacuum advance in terms of how much and when it comes in and stops. Crane used to make an adjustable VA and a detent plate kit to do this but no longer available. Homemade alternates for the detent plate have been done.

Pic of the Crane VA with detent plate installed to limit anount of timing advance it provides. Ideally you want 24 degrees of timing at idle with VA so 10-12 degrees base (no VA) and 10-12 of VA when connected and generally 35-36 degrees all in 2500-3k rpm.