Thread: 350 idle problems help please!!! holley 670

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At 4 vacuum your power valve is most likely active at idle. It will never idle correctly with the PV draining fuel into the carb. Standard power valves are usually come in at 6.5. Looks like you need a 25 PV. Better yet do the cam swap now.

Kitz

Kitz is right about the PV. Put a 2.5 in it. With this much cam, you also need more initial timing. Go with at least 20, with the total centrifugal all in by 2800. Plug vacuum into the manifold, not ported at the carb. If the starter kicks back on starting, interrupt the coil wire and install a momentary off switch. Push the momentary button, crank the motor to bring it up to speed, then release the momentary button and the motor will fire off. No sweat.
Also, check fuel pressure at the carb. No modern carburetor needs more than 5 psi pressure. More pressure than that WILL NOT MAKE MORE HP, it will simply over-power the needle and seat and blow raw fuel into the intake manifold.