Will:
Al's right, you're way over-carbureted, but take heart, LOTS of folks on here are over-carbureted!!
Also, if you have stock 1600 heads and you're not running bigger-than-stock valves in them, I doubt that those ratio-rockers are doing anything for you.
IMHO, if you went with a pair of 32-34mm Kadrons (no bigger than 36mm) and get rid of the stock exhaust for a decent header system you should be able to see close to or over 30mpg with that engine, plus a tad more power (but it's still a stock block, so don't expect miracles).
Lots of people with Speedies and more-or-less stock 1600's are seeing 28-30 on highways.....I have a nicely-built 2,110 with 40mm Dells and I'm getting 26-28.
gn