Author Topic: Spark Plug Gap  (Read 16640 times)

Offline 79K20

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Spark Plug Gap
« on: June 11, 2009, 04:24:34 PM »
What is the correct spark plug gap for a '79 350 4BB?

NAPA said 0.060", some old posts said 0.035"-0.045"...

I'm sure this has been discussed numerous times but I can't seem to find a straight answer in old posts. Thanks in advance.

Offline ccz145a

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Re: Spark Plug Gap
« Reply #1 on: June 11, 2009, 04:49:02 PM »
.035 was for point ign
I use .045.
With an upgraded ign system (high output coil) you can take it to .060.
1975 C10 Silverado LWB, 454CID, TH400, 10bolt 3.42
11MPG Downhill w/tailwind (but there ain't no hills here)

Offline choptop

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Re: Spark Plug Gap
« Reply #2 on: June 11, 2009, 10:42:50 PM »
General rule of thumb for what I have learned is .010 gap for every 10,000 volts
76 C10 Choptop,76 C10 Swb
85 C10, 85 K10, 85 K20,86 C10,86 K10 (all extended cabs)
86 C30 extended crewcab

Offline VileZambonie

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Re: Spark Plug Gap
« Reply #3 on: June 12, 2009, 04:57:54 AM »
what spark plugs are you using?
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline 79K20

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Re: Spark Plug Gap
« Reply #4 on: June 12, 2009, 08:37:45 AM »
AC-Delco, R44T, I think...

Offline VileZambonie

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Re: Spark Plug Gap
« Reply #5 on: June 12, 2009, 01:44:42 PM »
.035"
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10