getting constant vacuum on the ported vacuum port on my holley 600. why!!!!!!!. yes i'm sure it's the ported vacuum port.
thanx

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73 swinger holley 5200, 2 1/4" exhaust .030 over new pistons , cam, .010 under crank. stock everything else. 1/4 mile about a week. 0-60 around 15 sec.

maybe your idle throttle opening is too open.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

it's idling at 850 so doubt opening too far

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73 swinger holley 5200, 2 1/4" exhaust .030 over new pistons , cam, .010 under crank. stock everything else. 1/4 mile about a week. 0-60 around 15 sec.

OK, if the idle circuit on that carb ain't a match with your engine, you actually need to open the throttle more than neccesary to get it idling @ decent speed (keep it from stalling) I'm not familiar with that particular carb so I'm shutting up now, but someone here will help you.

In the meantime, you can remove the carb and inspect (naked eye) how far throttle blade is open at your present idle dialing.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Was it rebuilt by you or someone else? A wrong gasket could cause airflow to places its not supposed to.

I agree with Juan!

I just swapped a 360 into my Barracuda with a Holley 600 vacuum secondary. When I first started the engine I adjusted it for an 800 rpm idle and had vacuum on the ported vacuum port. As I got the timing sorted out and the idle mixture adjusted I had to keep closing down the throttle blades to maintain the 800 rpm idle. Once the throttle blade covered the port no more vacuum on the ported port.

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Dave Clement
68 Barracuda (Hot-Rod \6)
http://mysite.verizon.net/vze4pgxf/