Test and tune tomorrow

"You can quickent he secondary opening on the AFB design by removing some of the counterweight on the secondary air door. If you have gear and convertor, you may find it runs faster wiht it opening faster"

That is the key. I think if you can tune the secondaries and get the fuel curve right, the 750 will run faster. Look to the changes in the 600 to get the numbers it did. Holley's are easier to mess with by a long shot tho. Nice work in any case.