'86 Spark Plug Question?
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,970
Likes: 21
From: Denville NJ
'86 Spark Plug Question?
I have been running AC DELCO R43TS spark plugs in my '86 iron head. I bought new plugs today and the parts guy gave me AC DELCO R45TS plugs. He said that these are the correct part number and that they run hotter. Am I okay with these plugs or should I return them for the R43TS plugs. Thanks for any help
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
They are o.k. to use. I have the same R45ST in my 86E and they do fine, and they are a hotter plug than the R43ST. I only bought them because it was Sunday and Napa was closed. I usually use NGK in all my vehicles. I will be switching soon. 
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,970
Likes: 21
From: Denville NJ
Originally Posted by RRT vette
They are o.k. to use. I have the same R45ST in my 86E and they do fine, and they are a hotter plug than the R43ST. I only bought them because it was Sunday and Napa was closed. I usually use NGK in all my vehicles. I will be switching soon.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
Interesting. The AC Delco web site calls for the R45TS plugs in 1984 and the R43TS in 1985 and the iron headed '86, all with a .045" gap. These three years of engines are almost identical, except for the obvious induction system. Maybe the TPI runs leaner and favors a cooler plug. If the R43TSs were fouling, the R45TS may be just what you need.
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