Carburetors Carb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.

Timing?

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Old Oct 11, 2009 | 08:23 AM
  #1  
bljweeks's Avatar
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From: canada
Car: 84 trans am
Engine: 305 carb
Transmission: 700r4
Axle/Gears: 3.73
Timing?

I have a edelbrock 650 carb and performer rpm intake on my stock 84 trans am what should my base timing be set at? sticker under hood say 4 degrees but would u step it up a bit???

Last edited by bljweeks; Oct 11, 2009 at 04:15 PM.
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Old Oct 11, 2009 | 10:37 AM
  #2  
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From: canada
Car: 84 trans am
Engine: 305 carb
Transmission: 700r4
Axle/Gears: 3.73
Re: Timing?

Come on guys please help!
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Old Oct 11, 2009 | 12:42 PM
  #3  
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From: Fairview Heights Illinois
Car: 1986 Irocz
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.25:1
Re: Timing?

You set it to where it runs the best under most conditions without spark-knock and without hard starting when hot.
For the average carbed small block out there with non-computer controlled distributor, the best range is commonly between 10 and 15* of initial advance, not counting any vacuum advance.
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Old Oct 11, 2009 | 04:14 PM
  #4  
bljweeks's Avatar
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Joined: Aug 2009
Posts: 36
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From: canada
Car: 84 trans am
Engine: 305 carb
Transmission: 700r4
Axle/Gears: 3.73
Re: Timing?

Got it set at 12 from 4 and it seems to be running ok. Will i leave it there or step it up even more? why the big differeance in timing from 4 to 12 degrees like my sticker under the hood says??
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Old Oct 11, 2009 | 06:31 PM
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From: Fairview Heights Illinois
Car: 1986 Irocz
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.25:1
Re: Timing?

Originally Posted by bljweeks
Got it set at 12 from 4 and it seems to be running ok. Will i leave it there or step it up even more? why the big differeance in timing from 4 to 12 degrees like my sticker under the hood says??
When you change components like your carburetor, intake manifold, and distributor from stock, the optimum timing setting usually needs to adjust to fit the application.
Often you are getting either a cooler mixture or velocity has decreased in the intake port, which requires an earlier spark.
Actually many completely stock applications can gain performance with some increase in spark advance.
It's normal.
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