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73-87 Chevy _ GMC Trucks => Performance => Topic started by: 86Chevy3 on January 12, 2011, 07:29:32 pm

Title: Carb?
Post by: 86Chevy3 on January 12, 2011, 07:29:32 pm

I built a 383 recently and it seems like it needs to be timed or the carb needs to be adjusted, I timed it and it's still acting up so I'm thinkin it's the carb, I've tried adjusting it but I was wondering if I needed to change out the squirter nozzle or the power valve, it's flooding out but also backfiring, I've got it to where it idles pretty descent but it seems sluggish during low rpms and clears up higher in the rev range so I dint really know what I need to do, I'm thinkin about paying a guy I know to tune it up for me hopefully that's all it needs

Title: Re: Carb?
Post by: ToddN on January 12, 2011, 09:01:02 pm

Vac. leak?

Title: Re: Carb?
Post by: MITOYZ on January 21, 2011, 06:54:01 pm

sounds like a blown power valve, but dont know if its a Holley or not

Title: Re: Carb?
Post by: TexasRed on January 21, 2011, 08:23:38 pm

Stock carb, stock distributor? You have the vac. advance going to ported or manifold?

Title: Re: Carb?
Post by: 86Chevy3 on January 22, 2011, 05:29:55 pm

its a holly street avenger 670, proform hei distributor, and vacuum advance is hooked up to vacuum port on the carb

Title: Re: Carb?
Post by: Irish_Alley on January 22, 2011, 05:40:13 pm

Retard it a inch and go from there. I put my 670 at 8 degrees and something you saying retarded it and gave it that take off power you lacking not sure what it timed to now but much better

Title: Re: Carb?
Post by: 1980c10 on January 22, 2011, 11:59:18 pm

I have heard of an issue with proform distributors that allows the dist to turn on the shaft. so try to turn the dist by hand while watching the base if it moves without the base moving(by the hold down clamp) that would defintley be your problem.

Title: Re: Carb?
Post by: bake74 on January 24, 2011, 08:06:57 am

     One more option, I had a problem before like you said, at lower rpm it would backfire but at higher rpm it leveled out and ran fine, my headers were loose and after tightening them it ran better at lower rpm's..

Title: Re: Carb?
Post by: Grim 82 on January 24, 2011, 09:59:07 am

Quote from: 86Chevy3 on January 12, 2011, 07:29:32 pm

I built a 383 recently and it seems like it needs to be timed or the carb needs to be adjusted

Verify TDCC and make sure you have your firing order right. Set your idle mixture with a vacuum gauge if you have one. Was that a new carb, or one that was working fine before the 383 build?

Title: Re: Carb?
Post by: bowtieman82 on February 09, 2011, 04:08:13 pm

i know alot about holley cards. what jet size do u have now and size did it come with when was new. what is your elevation. what type of cam do u have how much comperion do u have. i have a 350 with a road deman, with a voo doo cam and a MSD HEI it make 400HP and it get 16 MPG in a 82 chevy 4x4 with 33's. soit u need help ask me.