Get a LM-1 meter. Properly setup and tuned a thermoquad would be real tough to beat. Easier to find and tune would be the Edelbrock.
I had a set of 750 eddies that I modified and tuned with my LM-1 on my tunnelrammed 528 hemi. It got an honest 10mpg driving it nice. The same motor and intake with a set of tuned 850 thermoquads netted me 13.18mpg, (driving it real nice). Dave