I have a crate 350 ci 250 hp in my '66. The stock jet is .098 and the metering rod is (075 x 047). To get better gas mileage what size jet and/or rod would I need? I'm getting about 11 mpg. The edelbrock booklet shows that I can change the jets from .092 to .101 and
the metering rod from 068 x 042 to
075 x 042. What does the metering rod do in conjunction with the jets?
THanks in advance.

WOAH! Dude! I get 16-18mpg in my 350/300hp 70 with that exact carb. Something's real funny there. I never changed rods/jets, just used it as it came. Something else is the problem here. Make sure the choke is fully opening, and the mixture screws are about 1.5 turns out from all the way in. If you never changed jets/rods, and just used it out of the box, you shouldn't be having this issue. I suspect something else is faulty.