timing L48
Le Mans Master
Joined: Oct 2006
Posts: 6,842
Likes: 285
From: Palmdale CA
I just happened to drive 'Sassy' (1974 L48) into work today. I'll check the timing decal. It's different for an automatic, versus a manual and I'll give you the details in a bit.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
Burning Brakes
Joined: Sep 2008
Posts: 805
Likes: 5
From: Naperville Illinois
Any reason you want to stick with the factory spec? The way I understand it, GM significantly detuned these engines and they can really benefit from a modified timing curve, especially a little more initial timing. The book spec on my '68 327 is 4 deg BTDC; I re-curved my distributor to run 12 deg initial and about 34 deg total (just over 50 with vacuum advance IIRC) and the car runs so much better--and cooler. 
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
There is more to setting the timing than a simple question. If all things are stock, and you want to set it to the stock setting, then some of the answers above can help. If you are setting the timing for best performance then the initial, mechanical and vacuum advance timing need to be checked, with the total timing i+m+v not exceeding 52 degrees.
Initial of 12 degrees can be a good setting, which may help to push the mechanical advance to around 36 degrees. I am hoping that others with more timing experience will join in at this point.
kdf
Initial of 12 degrees can be a good setting, which may help to push the mechanical advance to around 36 degrees. I am hoping that others with more timing experience will join in at this point.
kdf
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