info and advice please

i have a 302 with edelbrock performer manifold and 600 holley question is can i chop out all that vacumn piping that goes to the tree at front of inlet manifold as i figure i only need vacumn to gearbox mod ulator (c4) and cannister on dizzie at the moment i have a vac port blocked off under carb can i use that for dizzie and like i say ditch the rest thanks for any info and best way to go cheers mickmatt

That's how I have mine, transmission modulator and power brake off the tree at the rear, pvc to the back of the carb base, and distributor connected to front base of carburetor (full manifold vacuum port).

That's how I have mine, transmission modulator and power brake off the tree at the rear, pvc to the back of the carb base, and distributor connected to front base of carburetor (full manifold vacuum port).

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cheers Don C looks like i will be starting there tomorrow

i have a 302 with edelbrock performer manifold and 600 holley question is can i chop out all that vacumn piping that goes to the tree at front of inlet manifold as i figure i only need vacumn to gearbox mod ulator (c4) and cannister on dizzie at the moment i have a vac port blocked off under carb can i use that for dizzie and like i say ditch the rest thanks for any info and best way to go cheers mickmatt

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The vacuum port coming off the passenger side of the throttle plate on you Holley should go to trans modulator and the port coming off of the metering block(also on the passenger side) should go to your vacuum advance on your distributor. PCV to the back of the carb, and powerbooster to the back port on you Performer. Everything else can be removed and plugged off.

What's the PCV? anybody have a picture of the Holly 600 on a 302 with proper vaccuum lines hooked up?

I have my tranny vaccuum line going to the intake tree and not the port on the throttle plate...if I'm wrong, then that's why my tranny won't down shift when I get on it. It just revs then goes back into 3rd when I let off the accelerator.


What's the PCV? anybody have a picture of the Holly 600 on a 302 with proper vaccuum lines hooked up?

I have my tranny vaccuum line going to the intake tree and not the port on the throttle plate...if I'm wrong, then that's why my tranny won't down shift when I get on it. It just revs then goes back into 3rd when I let off the accelerator.

The PCV is the positive crankcase ventilation, a tube runs from the PVC valve in the top of one of the valve covers to a port under the rear/base of the carburetor. Check the inside of the hose running to the transmission vacuum modulator, if it has oil in it the diaphram in the modulator is bad. The modulator should be hooked up to a full manifold vacuum source, when the vacuum goes down the modulator holds the transmission in gear longer, or shifts it down sooner. A bad modulator, or absence of vacuum does the same thing.