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Old 07-11-2019, 03:37 PM   #1
Alex V.
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Join Date: Mar 2013
Location: Campbellsville, KY
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TBI>Carb/HEI timing

I've installed Holley Sniper on a 1990 K1500 with a stock TBI 350. Got rid of the defective (rusty inside) factory-style distributor and put a stock big-cap HEI in its place.

Right now I'm at:
4* base
25 @ idle
42 @ cruise
32 WOT.

I'm reading that the fast-burn heads don't need as much timing as older heads. I'm sure it can take more than where I currently have it, but since I'm not using Sniper to control timing I want to get it at a good, safe/conservative spot and leave it so I can get Sniper honed in around the advance curve. What timing numbers will be good, pretty guaranteed to protect the engine?
Alex V.
1967 C10 Suburban, 350/NP435, Green/Green, PS, PB, HD cooling, charging, shocks, and springs.

1985 GMC C3500 SRW, Sierra Classic, 454/TH400, white/blue.
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Old 07-11-2019, 05:36 PM   #2
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Location: Moss Bluff, LA
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Re: TBI>Carb/HEI timing

i just finished a swap, ...i have 12 initial at idle, MSD billet HEI and at 3500 i have 35*.

i have no pinging, it is very responsive and idles well for the cam.

i am running the fitech 600hp easy street efi, 91 octane

i would adjust to a point right below detonation, this will allow for better cooling, and overall fuel mileage as well.
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Old 07-11-2019, 08:36 PM   #3
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Location: Mesa AZ
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Re: TBI>Carb/HEI timing

A TBI engine does not have fast burn heads. I'd advance at least the WOT setting a bit.
-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle.
-98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes.
-02 Suburban 4x4: stock
-CBR600F4i, CBR600RR, CBR1000RR, and standup skis
DISCLAIMER: I cant spell for the life of me.
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