Carb for a 408

Could I hear from you guys with 408 small blocks running a 850 double pumper, what jets sizes work best so it doesn't fowl the plugs and do you use two power valves or one, or none? Thanks

Bigs 950 stage5+ which uses a proform 850 main body with 1.450 venture. 75/83 1 power valve in the front.

i use an aed 850 on my 418 stroker,pump gas.bought through competition wedge racing(todd).it has 79/88 jets,4.5 pv on the primary side,squirters are 37/40,works real well.mike

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Could I hear from you guys with 408 small blocks running a 850 double pumper, what jets sizes work best so it doesn't fowl the plugs and do you use two power valves or one, or none? Thanks

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I have recently learned that jet sizes depend alot on what carb you run as well as the specs of the motor.I bought one of the new Holley 850 ultra hp carbsand had 88&95 jets and never did get rid of a large stumble.I took it back and got a 850 Q-series Quickfuel carb and had to jet it down and its close with 74&82 jets.No powervalve in the rear and the Quickfuel carb has no stumble and works verry well.