Rochester q-jet bore diameter v cfm

[My68SS]

Just need to recheck myself on this.
800 cfm had 2.25" secondary bores?
What bore diameter did the 750 cfm have?
Were all primaries the same diameter @ 1.375" [1 3/8"] ?

[JohnZ]

All Q-Jets used on 1969 Chevrolet products had 1-3/8" primary and 2-1/4" secondary bores.

[My68SS]

I may have this all wrong anyway. This info http://buickperformance.com/qjet.html at the bottom indicates that it was the diameter of the annular ring in the primaries that determined the cfm of the q-jet.
I seem to remember reading this elsewere. Beware when reading it,  'Larger' = smaller diameter.

Here's another interesting read http://www.hemmings.com/mus/stories/2005/01/01/hmn_feature21.html
which half way down mentions that pre '72 q-jets were 750cfm and post '72 were 800cfm. Does this sound right?