>Question about Timing<

[Mobilehomie]

I recently had the heads rebuild on my son's '81 Sierra 1500. After much tweaking and tuning, I have replaced the carb with a re-manufactured unit, and have been messing with the timing. I don't think the mechanical advance is working. When I set the timing with truck in park, vacuum disconnected and port plugged I do not get any advance when I throttle it. When I hook up the vacuum it is only getting about a 10* curve. I realize the spec says to set initial at 6 degrees, I have always added ~ 2 degrees per 1,000 ft elevation (we live at 4,200 ft) so I have it at 12* initial and total is only 22*~ 23*....
Is that enough total advance? Should I just lock?

[Mobilehomie]

Originally Posted by Mobilehomie

I recently had the heads rebuilt and a new cam installed on my son's '81 Sierra 1500. After much tweaking and tuning, I have replaced the carb with a re-manufactured Q-Jet, and have been messing with the timing. I don't think the mechanical advance is working. When I set the timing with truck in park, vacuum disconnected and port plugged I do not get any advance when I throttle it. When I hook up the vacuum it is only getting about a 10* curve. I realize the spec says to set initial at 6 degrees, I have always added ~ 2 degrees per 1,000 ft elevation (we live at 4,200 ft) so I have it at 12* initial and total is only 22*~ 23*....
Is that enough total advance? Should I just lock the dizzy?

Only way I could figure how to edit.

[LONGHAIR]

No, that is not enough advance. You need to pull that distributor out and get it working properly. It will make a huge difference in how it runs and the fuel mileage.

[Mobilehomie]

Originally Posted by LONGHAIR

No, that is not enough advance. You need to pull that distributor out and get it working properly. It will make a huge difference in how it runs and the fuel mileage.

Thanks, I found this in the FAQ, makes perfect sence..

http://67-72chevytrucks.com/vboard/s...d.php?t=290498[/URL]