Thread: Headers = Carb Adjustments?

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306 (.30 over 302) with an Edelbrock 625 cfm 4-bbl. Took off my stock exhaust manifolds and installed a set of Hedman headers. 1 1/2" pipes and 3" collectors. Right now it's open at the collectors.

With the headers, it starts intermittently, has a tendency to die once it's put into Drive (C4 w/shift kit) and generally runs like crap. It was running great with the stock manifolds.

We checked for vacuum leaks and all the lines appear to be in place.

Has anyone else needed jetting or carb adjustment when installing headers?

Also, would this problem be lessened once the pipes are hooked back up?

- If so, would it return if I open up the Race Readies? (Blocked-off open 2 1/2" pipes.)

One final note: the next phase of this build is a hi-rise tunnel ram intake and dual 390 carbs. If having open pipes *does* affect tuning, should I have the exhausts put together before I install the intake and start tearing my hair out tuning the dual quads?

Thanks,

- Joey

To run correctly, headers with open exhaust require a jet change to compensate for the better scavenging of the cylinders.