383 carbed lt1 timing?
03-11-2008, 11:12 AM
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Car: 1991 Pontiac Firebird
Engine: 383 LT1
Transmission: built 700r4 and fuddle 3500stall
Axle/Gears: 4th gen 3.42 auburn
383 carbed lt1 timing?
The motor should be ready to fire this weekend and i was wondering what i should set the timing at?
Its an internally balanced 383 stroker running roughly 11.5:1 cr with a 234/242 .520/.540 112lsa aggressive lobe profile cam
heads are stock castings that have been fully ported at SAM flowing in the 270cfm area.
Im running a 650cfm eddy thunder avs carb on it for now with a 1 or 2" spacer havent decided what would be better yet and some tr6 plugs.
Its an internally balanced 383 stroker running roughly 11.5:1 cr with a 234/242 .520/.540 112lsa aggressive lobe profile cam
heads are stock castings that have been fully ported at SAM flowing in the 270cfm area.
Im running a 650cfm eddy thunder avs carb on it for now with a 1 or 2" spacer havent decided what would be better yet and some tr6 plugs.
03-11-2008, 02:29 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Gen I SBC's like 34-36 degrees total mechanical timing. Vortec headed Gen I's seem to take a little less, like 32 degrees total mechanical. I would guess that the LT1 is more like the Vortec, so I'd say shoot for 32 total and test from there.
03-13-2008, 08:48 AM
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Car: 1991 Pontiac Firebird
Engine: 383 LT1
Transmission: built 700r4 and fuddle 3500stall
Axle/Gears: 4th gen 3.42 auburn
Re: 383 carbed lt1 timing?
what should i set the base timing at? i was thinking 15-17 with 32 total all in by 3000rpm
whats the stock lt1 timing set at?
whats the stock lt1 timing set at?
Last edited by gapimpin; 03-13-2008 at 09:00 AM.
03-14-2008, 08:36 PM
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Car: '83 Z28, '07 Charger SRT8
Engine: 454ci, 6.1 Hemi
Transmission: TH350, A5
Axle/Gears: 2.73 posi, 3.06 posi
Re: 383 carbed lt1 timing?
Its not - its a non-adjustable system if you use the Optispark and ECM. It only bolts on in one position and the ECM puts the timing where it wants it.
Something between 12-15* initial and around 32* total @ 3000rpm is a good start. The LT1 heads are VERY similar in design to the Vortec heads, so they behave similarly with the same changes.
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