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Dual quad question...help needed.

64SF

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I recently installed an Offenhauser 360 dual quad intake with two rebuilt Holley 600 CFM vacuum secondary carbs (1850-3) on my 451 engine. During the rebuild I didn't change the stock jets or metering plate. The installed front jets are 66 and the metering plate is 134-9 which Holley shows as the stock set up out of the box.

I've got a problem starting the engine in the throttle idle position...it will only start when the accelerator is in the full throttle position (like starting a flooded engine). The two throttle are connected directly together. No progressive linkage. In reading about the 360 Offenhauser the front carb feeds the front two cylinders on each bank and the rear carb feeds the rear two cylinders on each bank...at least that's what I understand...I could be wrong.

Would the idle circuit jet be to large for the 4 cylinders it feeds and causing a flood situation on start up?

I removed a 750 Quick Fuel/RPM intake...the car ran fine with the setup. I change nothing other than the intake and carbs.

Any thoughts or suggestions would be greatly appreciated. Thanks
 
If you have to hold the throttle wide open to start my bet is fuel is dripping into the manifold. Blown or loose power valve, high float level, leaking needle/seat, leaking seat o-ring, high fuel pressure.
Doug
 
sounds like the above poster's opinion - Do you get black smoke or rough running on initial startup ? If there are signs of a very rich condition you problem have a stuck needle/seat, float level adjustment issue, etc as listed above.
 
Will be doing the float check tomorrow and post the results.
I’m thinking that this is the problem.
 
Float level, vaccum leak and a new set of plugs fixed the problem. It’s running, starts just needs some tuning tweaks. Thanks for the help.
 
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