Which Spark Plugs?
Thread Starter
Le Mans Master
Joined: Nov 2003
Posts: 5,772
Likes: 694
From: Maryland
St. Jude Donor '05, '09, '15
Which Spark Plugs?
My car is a 65 but I have a 69 350 engine. I was looking at the AC Delco web site and looked for spark plugs by model. A 66 Corvette, doesn't have 65, 327 calls for R45S. A 69 350 Corvette calls for R43S. So. Which plug do I use? I would think the R43S to match the engine. However. I looked the C3 section and the recommended plug there seems to be the R45? Thoughts?
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
My car is a 65 but I have a 69 350 engine. I was looking at the AC Delco web site and looked for spark plugs by model. A 66 Corvette, doesn't have 65, 327 calls for R45S. A 69 350 Corvette calls for R43S. So. Which plug do I use? I would think the R43S to match the engine. However. I looked the C3 section and the recommended plug there seems to be the R45? Thoughts?
R45 or R45S or equivalent in another brand.
Safety Car
Joined: Feb 2006
Posts: 4,367
Likes: 59
From: FL
My car is a 65 but I have a 69 350 engine. I was looking at the AC Delco web site and looked for spark plugs by model. A 66 Corvette, doesn't have 65, 327 calls for R45S. A 69 350 Corvette calls for R43S. So. Which plug do I use? I would think the R43S to match the engine. However. I looked the C3 section and the recommended plug there seems to be the R45? Thoughts?
There is no real performance difference in the 45 or R45. The R is for resistor plugs which help reduce ignition noise in radios. The R45S has an extended tip which helps keep it cleaner from fouling and so it runs a bit better. However, if you have high domed pistons or the heads have been shaved, you could hit. You need to install the plugs, turn the engine over, and then check the plugs if you have any performance work done on the engine.
If you are running the R43S, you'd better be doing hot laps most of the day, because it is far too cold for the street.
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
The original setup used nonresistor 44 plugs with resistor wires. If you use resistor plugs such as R45, and you have the original Delco coil, IMO switch to nonresistor wires or bag the original and expensive coil.
The original coil is easily overloaded by resistor plugs used in conjunction with resistor wires. So was the Pertronix Flamethrower thatI replaced it with - that lasted about a year before melting down.
The original coil is easily overloaded by resistor plugs used in conjunction with resistor wires. So was the Pertronix Flamethrower thatI replaced it with - that lasted about a year before melting down.
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