"I have a letter dated July 12, 1968 from Carter Carburetor Division which was in response to the question I asked about the carb CFM rating. Letter said; the 3506S Carter (R-1) has a rating of 637 CFM @ 2" mercury. Avanti, 1
Carter Carbs Specs for R - Engines R1 - Carter AFB 1 7/16" primaries, 1-1 1/16" secondries model 3506s flow 625 CFM (+-10) Replacement = Carter CRT-9635 or Edelbrock 1406 Jets: .089" (120-159) primaries; .058" & .069 (16-99) metering rods. Secondary jets were .077" (120-177)
R2 - Carter AFB 1-7/16" primaries, 1-11/16" secondries Calibrated and sealed Stude# 1561641 model AFB-3606 flow 625 CFM (+-10) Replacement Carter CRT-9635 or Edelbrock 1406 ( Use Procharger bonnet to adapt supercharger hose)
R3 - Carter AFB 1-7/16" primaries, 1-11/16" secondries Competition model Stude# 1558637 Standard model 1563050 model AFB-3808S flow 625 CFM (+-10) Primary jet # 120-159 Size (.089) Secondary Jet # 120-166 size (.0935) Primary metering rod # 16-103 size (.068 X .060) float setting 13/32"
R4 - Carter AFB 1-9/16" primaries, 1-11/16" secondries Front Carb Standard model Stude# 1563051 AFB-3810S flow 675 CFM (+-10) Primary jet # 120-162 Size (0-1015) Secondary Jet # 120-176 size (.0635) Primary metering rod # 16-124 size (.069 X .0635) float setting 5/16"
Rear Carb Standard model Stude# 1563051 AFB-3811S flow 675 CFM (+-10) Primary jet # 120-162 Size (0-1015) Secondary Jet # 120-122 size (.070) Primary metering rod # 16-204 size (.073 X .063) float setting 5/16"
Front, without choke Stude# 1563051 Rear, with choke 1563052"