I need some help please.

I have a 429 that was just rebuilt to stock specs,except for the 280 magnum Cam & chain.
It has a Holley 750 Vac/secdrys.When I try to plug the vacuum advance on the dizzy,it pops threw the exhaust and kills the engine.
Can anyone help?

TERRY

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Do you have the valve timing and initial ignition timing set right?
Double check those things.

 

If you have your vacuum hose connected to manifold vacuum it would raise the idle speed which would necessitate that you lower the idle at the carb idle speed screw. Then when you pull the vacuum hose your idle is too low to keep the engine running. If you connect the vacuum hose to the port on the Holly just above the idle mixture screw (ported vacuum) you should not have any (or much) vacuum at idle so you can readjust (raise) the carb idle screw. On my Holley I get no vacuum to distributor at idle until the throttle opens - so the idle speed does not change with or without hose disconnected.

 

Then there are some engines with that temperature switch on a tee fitting, that diverts vaccuum to manifold when it gets hot idling, to give a faster idle to cool the engine... Otherwise, vac supply is from the carb
Mark


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