This was an 850 cfm unit that I cut the lower ring out of the primary venturis and eliminated the power piston on. Also had the choke plate and shaft eliminated. Was setup to flow ~925 cfm or close to it. Even on a near stock ~165 hp 305, no quadrabog bogging noises, just a seamlessly smooth increase in power as the engine reved out. If you can feel the secondaries open on the Q-Jet they are opening too early. th-cam.com/video/Tvay9zOW6hE/w-d-xo.htmlsi=Rnh2NarMB0tCRYCP
@@chrisreynolds6520 I must have 10 - 15 a these carbs on hand i can play with. all 650's cept i do have 1 850 , so what does cutting the ring out of the bottom do ?
@@chrisreynolds6520 So when you eliminate the power piston are you turfing the metering rods too (as thay r part of the PP) and going to a strait jet set up ? sounds like an interesting mod , tell me more !
@@luckyPiston When you want more CFM on the primaries and do not care about the off-idle and fuel mileage the booster rings go. I set them up like that for RVs, tow vehicles, boats and racing. Adds about 50 cfm to the primaries. Pontiac actually made some of their performance carbs the same way in the late 60s. Will need to go up 4-6 jet numbers. 72 jet would need to be 76 minimum.
Pretty snappy on the primaries , gotta whack open the secondaries ta get that guttural Q-Bog sound
Properly dialed in Q-Jet will never open the secondaries up on an unloaded free rev throttle snap like that.
This was an 850 cfm unit that I cut the lower ring out of the primary venturis and eliminated the power piston on. Also had the choke plate and shaft eliminated. Was setup to flow ~925 cfm or close to it. Even on a near stock ~165 hp 305, no quadrabog bogging noises, just a seamlessly smooth increase in power as the engine reved out. If you can feel the secondaries open on the Q-Jet they are opening too early.
th-cam.com/video/Tvay9zOW6hE/w-d-xo.htmlsi=Rnh2NarMB0tCRYCP
@@chrisreynolds6520 I must have 10 - 15 a these carbs on hand i can play with. all 650's cept i do have 1 850 , so what does cutting the ring out of the bottom do ?
@@chrisreynolds6520 So when you eliminate the power piston are you turfing the metering rods too (as thay r part of the PP) and going to a strait jet set up ? sounds like an interesting mod , tell me more !
@@luckyPiston When you want more CFM on the primaries and do not care about the off-idle and fuel mileage the booster rings go. I set them up like that for RVs, tow vehicles, boats and racing. Adds about 50 cfm to the primaries. Pontiac actually made some of their performance carbs the same way in the late 60s. Will need to go up 4-6 jet numbers. 72 jet would need to be 76 minimum.