Thanks for explanation guys, I get it!
I had heard of drilling out out a port in the metering block (PVCR) before, but really didn't understand the process due to my lack of knowledge and/or a poor explanaton. But now I see.
My carb guy made mention of this. He showed me a box of metering blocks (about 10-12 blocks) and they were all labelled with the size that they were drilled.
I've mostly read and heard about the 'trial and error' method(voodoo system) of carb tuning. Basically keep trying different combinations of this and that until you're happy, and when you are happy it's a mystery as to exactly what was done (VOODOO! - I hate it).
So, for the 1st step, I'll be changing jet size and monitoring mileage closely. Based on your experiences, do you guys think a #59 MJ is reasonably close jet size or should I start smaller or stock (my carb guy was real clear that most of 390's he rebuilds are not for inlines)? Or isn't there a good way to determine an appropriate MJ size due to too many variables?
