# timing question



## 67lemans (Oct 30, 2009)

My car has a 1970 pontiac 350, 4bbl. I've had trouble locating the proper timing but I think it is 12 degrees. 1) Can anyone confirm that?

I read the recent timing post describing to time at idle, vaccume line disconected and plugged, so I did that to 12 degrees. 

2) when the vacumme is reconnected at idle, it advances right away to what I'd guess to be about 18-20 degrees, and really speeds up the idle to around 1,000. Is that normal and should I just back off the idle back to around 700 rpm? 

3) upon suddenly/quickly opening the throttle (flooring it) there is a little hesitation, almost like a back fire, but not quite. I notice when I do this the timing drops way back to around 12 degrees for an instant and then as it revs it goes quickly back to around 35 degrees or so. (about to where the lower left bolt on the water pump is anyway). 

I'd like to get rid of that hesitation if possible. Carb is an edelbrock 600 cfm and I've used both the timed and untimed ports for vaccume advance, only difference is at idle of course. 

Any suggestions would be appreciated. Thanks


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## jetstang (Nov 5, 2008)

Base timing should be at 6, not 12, and back it off because of bad gas. Tune it to 36 as stated in the other link. I only use ported vacuum.


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