Originally Posted by F-BIRD'88
Just don't get too carried away on trying to get it tuned too sharpe. ( best power) You need some in cylinder cooling (extra fuel) to keep it alive under boost. You don;t want to be on the edge. A bit rich er Under boost/throttle is fine. You can drill/hone the jet hole in the sec metering plates to fatten that side up if needed.
I'd use a minimum of a holley #21 sec metering plate in the 600VS carbs. These are found in the 3310 VS 750 holley carb.
Was it pig rich with #72 pri jets in it.? ( I assume that you had the power valve in.) Starting rich is the safe way to tune it in.
If its tuned on the edge with a #65 you may want to bump up to a #67ish pri jet. A bit rich is best.
The secondary metering plate matters. Its not that hard to modify/convert to replaceable holley jets.
How much vacuum did the wide open throttle carbs pull at WOT? max rpm. What is the blower drive ratio?
Indicated boost @WOT.
10 -11 psi can be achieved but will not be revving that hard for a good while or stepping on the gas.
I did a reading a while ago from under the carb base plate and it was around 15 hg vacuum
am running 70s in the primary's not 72s but still pig rich
I presume once I change down a jet I will know if its better as the air mix screw will start to operate ?? or with the sec throttle blades open will that also not allow the air mix screw to not function ?