It looks to be a Speed Demon
With the butterflies showing 1.69 I figure that to be 1 11/16".

I have the chart showing 1 11/16" vacuum sec. being either 650 or 750 CFm depending on venturi size.
650 is 1.28 and 750 is 1.40 venturi
Boosters are downleg
650 is .140 750 is .160

I hope this helps.
Mark


1996 Ram 1500 Sport
1968 road runner
1952 Sears Allstate licensed, pump gas, Hemi 5.98 @ 115.73 1.33 60 ft. The best is yet to come. Painless Performance / Street RODDER magazine Top 100 for 2019