SBC distrib one way valve?????

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Sep 11, 2006
San Jacinto, CA
This is the deal 307 chevy stock distrib (not HEI) with a one way valve on the vacume line. I have been trying to figure out why it sputters when giving a little throttle to it mostly happens in 2nd and third gear. I have played with the timing a bit rebuilt the carb (EDL) but still it happens. Sunday decided to pull the one way valve off and run the vacume line direct to the distrib... big diffrence it acted like it was running on four cylinders ran real rough. My question is, is this valve needed and if so what is it's purpose? Im not sure if it is keeping the distrib from advancing as it should. This weekend I will probably pull the valve and re-time again to see if it helps. Just wondering! :confused:
Howdy! A oneway check valve on that vacuum line move will cause the vacuum advance diaphram to stay activated(advanced) once the engine/carb has created enough vacuum to move it. Should not have one. It may be a left over from some other smog gear. Which carb, and which vacuum source on the carb are you using for the Dizzy advance? Should be NO vacuum at idle, then good vacuum just after throttle is opened a bit. John
Gone it is then! Just wasnt sure if it had a purpose or not. PO did a lot of crazy stuff on this one. Carb is a EDL 600cfm non egr, vacume hooked to small port on pass side no vac at idle just when throttled up. 68' 307 chevy stock distrib as far as I can tell. Thanks for the input.:clap:

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