Dual Quad Tuning

[kountzecobra]

Well, I am just about through with my 8v Low-Riser intake manifold for my 351 Cleveland. I will be using (2)- 390 cfm Holleys with vacuum secondaries and linkage for 427 Med. Riser. Do any of you dual-carb gurus have any suggestions for me when I start setting up linkage and start tuning carbs? I have never fooled with multiple carb setups, so there may be some learning curve involved, so I thought maybe I can benefit from other's experiences. Both carbs have chokes, so should I remove one? Vacuum diaphrams will be connected. I also installed air/fuel ratio meter to help tuning. Thanks, David Shelton.

[Mr.Fixit]

On dual quad setups, I always remove both chokes. Often mill the choke horns off the main body. I also install downleg boosters in both carbs (holleys). I remove the 3/8" vacuum line nipple from the baseplates and tap the holes for pipe plugs. Connect the vacuum pots together with a jumper hose. The linkage I use has a bellcrank so the carbs go on backwards. Make sure you have the good float bowl vent baffles so you don't flood the motor while braking. I also recommend that you put a little bit of progressive into the linkage on the rear carb so it comes in a 1/8" sooner than the other carb. Out in fresh sparkplugs and start the tuning.