Inliners International Forums General Discussion Engines Idle Speed - Dual Rochester DC Carbs

There are 4 different throttle disc diameters, in 2 bolt patterns: 1-1/2", 1-9/16", 1-11/16" and 1-3/4".
In addition, several were made with multiple venturi sizes:
1-1/2" with 1-1/16", 1-7/32" venturis
1-9/16" with 1-3/16", 1-9/32", 1-11/32"
1-11/16" only with 1-15/32"
1-3/4" with 1-9/16", 1-5/8"

Total of 8 sizes.