The Stovebolt Site Forums The Shop Area Engine Shop AC 46-5 Spark Plugs...

Is anyone familiar with AC 46-5 spark plugs, and can they be used on a 216 engine? If not mistaken, the factory plug was a AC-46...

If your 216 uses 14mm threaded spark plugs, they will work, but may be one range hot. The '50 VIKs at the GM Heritage Center Archive site list the 46-5 as original for cars with the 216, and the 44-5 as original for truck 216s. For a lightly driven truck, the hotter plug may be a good choice.

Since the "dash 5" plugs are in demand for "correct" restorations, and not terribly common any longer, I have a couple sets on the shelf, and run modern AC plugs in my Chevys, FWIW.

FYI, you may find the VIKs HERE, if you've not accessed them in the past. Lots of great info. Select the link for car or truck, scroll down the your model year, and the .pdf of the original Chevy documentation will open.

Doug

Hello Doug,

Thank you very much for the great info... I just opened up the GM Heritage files (pg.59) and found the AC-46 (14mm) spark plug listed to be standard for 1939 trucks... Find it interesting that the 1950's reference would be different, but I'm not surprised... On the other hand, it makes sense for trucks and cars to have different plugs, since they used different carburetors and trucks worked much harder... So, I really wonder how much of a difference a "dash 5" plug would make compared to the regular AC 46; or what is the tempersture difference...

I'm not so much asking to have a correct plug for judging, but because I can buy 30 of them at a reasonable price...In my case, I would just use them if I thought that the engine would benefit greatly...

Well, you are stressing my foggy memory here, but as I recall, the dash 5 plugs were broader heat range. Frankly, I doubt you would see any difference in engine performance, so long as "reading" the plugs shows the heat range is OK.

One thing to note, since the dash 5 plugs are used for restorations, you might want to pick them up and resell. They bring a fair bit of $ on eBay these days. Just a thought.

Doug

I wondered what you recalled from personal experience, or if you ever run a test, say using one or two dash 5 plugs with the regular 46's, running the engine, looking at the color and feeling the temperature difference just in your hand... Unless you could have access to a tempersture probe to really see what the difference is... That might be the only way to go, since plugs get very hot, and hot is hot in your hand!..;)