I know the basics of how the holley carb tuning works. You pull out the metering blocks between the bowls and body and replace the jets, and you can change the power valve right? That's pretty much the extant of what I know. On my current carb, I have vaccuum secondaries, so I also know you have to swap out the spring for that, but that won't apply to whatever I get next. For edelbrocks and the street demon I just know there are jets somewhere and that you unscrew a cover to replace metering rods and springs. I know they all also have the idle mixture screws and I know how to adjust those. What makes one more tunable than the other? are the metering rods a less precise way of doing things than the metering blocks of the holleys? I know the DPs have 4 idle screws as opposed to 2, but isnt that just because the others run on two smaller barrels to save on fuel until the secondaries open?
