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Old 07-31-2013, 02:22 PM   #108
Rufton
Registered User
 
Join Date: Apr 2013
Location: Knoxville TN
Posts: 1,170
Re: 1966 GMC 305 V6 Service

Distributor seems to be behaving. I wanted to dial in a couple more degrees but advance already looks good relative to some other engines. Not sure if I ever hit mechanical advance stop; didn't wan't to spin it faster cause not confident in tach accuracy (indicates low compared to car tach).

7-31-2013 66 GMC 305E V6 timing data:

Timing (vacuum advance connected, cold engine):
6* 490 RPM
24* 1000 rpm
42* 1500 rpm
45* 2000 rpm
48* 2500 rpm

Timing (vacuum advance connected, warm engine):

9* 600 rpm
16* 1000 rpm
16* 1000 rpm
42* 1500 rpm
46* 2000 rpm
49* 2500 rpm
55* 3000 rpm

Timing (vacuum advance plugged, warm engine):

9* 600 rpm
16* 1000 rpm
25* 1500 rpm
29* 2000 rpm
33* 2500 rpm
38* 3000 rpm

Dwell (warm engine):

31 dwell 620 rpm
30 to 31 dwell from 620 to 2500 rpm.

Timed vacuum port Stromberg WW:

<2” Hg 620 to 900 rpm
4” Hg 950 rpm
6.5” Hg 1000 rpm
13.5” Hg 1200 rpm
15.5” Hg 1500 rpm
18.5” Hg 2000 rpm
18.5” Hg 2500 rpm
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