OK while you're in there: * On the carb air horn there should be a number, like LIST 6390 or LIST 8007 And then a 3 or 4 digit date code, can you read those?
Then on top of the metering block there should be another number, like 6946 That might tell us what goes together.
To measure the PVCR holes you have to take that power valve OUT, then there are 2 small holes drilled in the metering block, they will be about .028" or so. Worth doing while you're in there so you know whats what and if anybody was in there playing with it.
The jets should be stamped with a number on the side. I used to be able to read them from a mile away but now I use a magnifying glass. Of course, make sure nobody drilled em else who knows what size they are.
On the main body, there are 4 brass inserts inside the choke horn area near the boosters. These are air bleeds, it would help if you can measure those too. The inner pair are the main air bleeds. On my 6390 carb they are .000" ie not drilled. The outer pair are the idle air bleeds, they are .067" on my 6390 carb.
Also, while the metering block is off, clean it with gasoline, thinner, acetone, blow every hole with lots of air, anything you have. Cant hurt and is sometimes the problem.
