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rough idle!

1568 Views 6 Replies 5 Participants Last post by  Henry Highrise
i recently rebuilt my `79 chevy 305, i added a high pro cam and a big holley carb !
my problem is now, three months later my engine is idling badly until i remove the pcv valve (wich has been replaced several times)!
does anyone have a idea of where i may have gone wrong?

the cylinder heads came off a chevy 350, the intake is stock.
next week i plan to purchase new heads and performance intake. can this solve my problem?

reggiesr <img src="confused.gif" border="0">
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What do you mean idling bad? What size carb did you put on the engine and what is the lift and duration of the cam? Did you ask the cam company for a recomendation or go with the big lift? The more radical the cam the higher idle your going to see. Your cam maybe good for track and bad for the street. Talk to the cam manufacturers rep, he should give a starting point to solve the problem. The Car Nut Joe
I can't tell you why (I'm sure someone will be telling you soon though), but 350 heads will not work on a 305. The 305 is the only small block chevy that you can't exchange heads on. It's probably amazing that the motor ever started at all.
Reggie: It sounds like you have a vacuum leak associated with the PVC plumbing. Block off the pvc and see if it runs more smoothly. Be sure that all your hoses are plugged in properly and that you have no open plugs in your carburetor, intake manifold etc.
reggiesr, got your e.m., and yes you can e-mail me direct if you have any other ?'s just make sure I have a reply address. I just got back into rodding about 2 years ago and I'm kinda relearning things that I once knew alot about, so don't always take my word or anybody elses as the final word. Except maybe Roy.
Hi Reggie, e-mailed you it didn't go through. get me your address, i'll try to help out where I can. Joe the Car nut
I will have to go along with Joooooe, I thought the only heads that would work with a 305 were 305 heads. Maybe that is your problem.
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