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Old 09-02-2019, 10:52 AM
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unruhjonny unruhjonny is offline
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Join Date: May 2004
Location: Calgary, AB, Canada
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Quote:
Originally Posted by TransAm 474 View Post
What AC Spark Plug should we run in this? Just want to make sure we get the heat range correct. Just as a reminder, these are 12 heads, big plug......
the 100% correct one is an NLA R44S;
many here have had luck using the one step hotter R45S which is currently available.

I have had good experience with the Autolite 85;
The Autolite 85 seemed to run better than the R43S which is a cooler plug than OE.

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1970 Formula 400
Carousel Red paint on Black standard interior
A no-engine, no-transmission, no-wheel option car.
Quite likely one of few '70 Muncie three speed Formula 400's left.


1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing)
2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs)