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Base timing?

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Old Sep 5, 2010 | 02:33 AM
  #1  
86Z28beast's Avatar
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Joined: Jul 2007
Posts: 42
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From: Houston
Car: 86 Iroc Z
Engine: Built 305
Transmission: 700R4
Axle/Gears: 3.73
Base timing?

Just got my car back on the road after 2 yrs but I don't remember what the base timing should be set at. The car runs o.k. but I have the base timing set at 14 degrees. Seems like the car is low on power for what it is. Running a built 305 10.5 comp with ported heads and 520 lift 296 duration cam with a stock maf tpi setup. What should the base timing be set at or am I good with it set at 14 degrees? Thanks
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Old Oct 12, 2010 | 12:19 AM
  #2  
camostang's Avatar
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Joined: Feb 2010
Posts: 17
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From: BC, Canada
Car: 1991 camaro z28
Engine: LSX
Transmission: T56
Axle/Gears: 3.55
Re: Base timing?

oem base timing is usually set at 6 * btdc
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Old Oct 12, 2010 | 12:32 AM
  #3  
AlkyIROC's Avatar
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Joined: Jul 1999
Posts: 17,262
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From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Base timing?

You need more base timing than 6* for that cam. According to Barry Grant,

10-12* for a camshaft with less than 220 degrees @ .050"
14-16* for a camshaft with less than 240 degrees @ .050"
18-20* for a camshaft with less than 260 degrees @ .050"

However when you advance the base timing, you're also advancing the total timing. If an engine runs best with 34* total timing and you bump up the base timing an additional 10*, your total timing moves to 44* and you lose power. The mechanical advance then needs 10* taken out of it to bring the total timing back to 34*.

Leave you base timing at 14* and see what your total timing is at. For best performance, timing should be at full advance by 3000 rpm.
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