[Jeff Lee]

To clarify, the 4300 Autolite is different from the 4300D Autolite in that the D series is a spreadbore with larger throttle blades than the 4300 "non D", correct? I believe the 4300D was rated at about 715CFM. Correct me if you have other info (I run the 4300 non-spreadbore).
And I probably should not reference this as a "spread-bore". Square flange or spread-bore flange may be more accurate.