Carb suggestions - Page 2 - Chevelle Tech
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post #16 of 26 (permalink) Old Mar 14th, 20, 12:26 AM
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Re: Carb suggestions

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Originally Posted by BCarter72 View Post
I'm not mechanically sound..... how do you measure that? I know at idle with vac advance hooked up under the carb I'm at 16 degrees according to the timing light I have
If you have an hei, it probably has 22* of mech advance. Set it to 14* which should give you 36* total. Then plug in your vacuum advance and see where it is at idle. If it has a 15* can, it will be too much at idle. But you can idle it and see if that cleans up your idle smell. Then either get a can with less or limit what you have.

If you have a msd type where you can change bushings, that makes life easier.

I have an 800 Edelbrock on my wagons 454, it idles clean. They are pretty nice carbs once ya figure them out. Car show carbs...funny stuff.

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post #17 of 26 (permalink) Old Mar 20th, 20, 7:31 PM Thread Starter
 
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Quote:
Originally Posted by Reelysalty View Post
“And sitting with 16 degrees total timing”

Should have around 35 total timing all in about 1600 and 20-25 idle timing, Vacuum adv on bottom of Holley
On the "full manifold" port instead of the "timed vac source" on the front side of the carb?
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post #18 of 26 (permalink) Old Mar 20th, 20, 7:49 PM
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Quote:
Originally Posted by BCarter72 View Post
Quote:
Originally Posted by Reelysalty View Post
“And sitting with 16 degrees total timing”

Should have around 35 total timing all in about 1600 and 20-25 idle timing, Vacuum adv on bottom of Holley
On the "full manifold" port instead of the "timed vac source" on the front side of the carb?
Yes, full vacuum is the small (1/4” ?) angled port on front right, and angled right of carb, under front bowl, Be sure similar port at top of carb is plugged.

When you set timing, pull off distributor vacuum hose and temporarily plug its’ port. Set timing to around 34” at 3000, should be same at 4000 also. Remove light reconnect vacuum hose to bottom of carb and you should be OK !
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post #19 of 26 (permalink) Old Mar 20th, 20, 8:30 PM
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Seems my Holleys end up idle mixture screws 3/4 turn out
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post #20 of 26 (permalink) Old Mar 21st, 20, 9:16 AM
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Re: Carb suggestions

Why is there a single plane intake on a "stockish 402"? I'd put a dual plane on there to start with.
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post #21 of 26 (permalink) Old Mar 21st, 20, 10:01 AM
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Originally Posted by nitrofox View Post
Why is there a single plane intake on a "stockish 402"? I'd put a dual plane on there to start with.
I missed this ^^^^ !
IMO, this might be the whole problem.

Sometimes there isn’t any forest, just some trees. LOL
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post #22 of 26 (permalink) Old Mar 21st, 20, 9:00 PM
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Re: Carb suggestions

In order to make any differance at all you have to drop 3 jet sizes example if you have 72 jets you need to drop to 68 3 full sizes between the numbers you have . I have re jetted many a holley on both sides, but mostly on the primary. This of course is all dependant on the combination of parts cam tranny rear gear and other stuff headers msd etc etc. Alex
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post #23 of 26 (permalink) Old Mar 21st, 20, 9:04 PM
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Re: Carb suggestions

I forgot to say why do you have an open plenum . You should use a dual plane on just about everything street driven. The g/m engineers thought so. Single planes are mostly for purpose built engines. Alex
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post #24 of 26 (permalink) Old Mar 22nd, 20, 11:27 PM
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Re: Carb suggestions

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Originally Posted by BCarter72 View Post
I have a stock-ish 402 with oval heads, single plane intake, and headers. Currently have a 770 holley street avenger with stock jets and power valve. She is running way too rich with the needles damn near closed. Am I wrong to think the this carb is too much... suggestions on what to do or move too
A stock cam with a single-plane intake ? No wonder it's a dog LOL

Just kidding. If it was mine' I'd run a stock intake with q-jet or a performer with the new street demon from Holley.

The street demon is a very nice modern-type q-jet design

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post #25 of 26 (permalink) Old Apr 9th, 20, 8:24 PM Thread Starter
 
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Thanks for all the help folks!!! I got her back from tuning death... turns out I wasn't going to initial 8 degrees... only 6.... I cleaned the piss out of my timing tab and pulled my carb and went down 3 jets front and back. Was only getting 11hg vacuum at idle... dropped down 1 size power valve. Now I'm at 8 degrees initial timing and 34 degrees total with no problems... had to rebuild the top end of the distributor and went through 2 sets of plugs... but worth it to get her back on the road. THANKS AGAIN for all the knowledge and help!!!
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post #26 of 26 (permalink) Old Apr 9th, 20, 8:30 PM
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Glad you got it running right !
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