There have been several variations of venturi on "950" carbs. But these are my old notes:

Holley 950 HP.......1.375 X 1.750
Holley Ultra 950 .. 1.600 x 1.750

Proform 950 .....1.450 X 1.750
QuickFuel 950 ...1.450 X 1.750


1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1