Spark Plug Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sjarrett71 · 11-30-2012, 11:48 PM

Looked up some spark plugs at the auto parts store and noticed there were several recommended. I chose to go with AC Delco but there were still several different numbers to choose from. Some had washers, some had tapered seats. I went out to the parking lot and pulled one out of my 72 with a 350. It ended up being the plugs with a washer. The number on them was R46S. Since they don't make an R46S anymore, I bought the R45S's.

My question is, what is the difference between the heads that take a tapered seat versus the heads that take a washer'd spark plug. My experience with Chevy engines has been with tapered spark plugs.

11-30-2012, 11:48 PM	#1
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Spark Plug Question Looked up some spark plugs at the auto parts store and noticed there were several recommended. I chose to go with AC Delco but there were still several different numbers to choose from. Some had washers, some had tapered seats. I went out to the parking lot and pulled one out of my 72 with a 350. It ended up being the plugs with a washer. The number on them was R46S. Since they don't make an R46S anymore, I bought the R45S's. My question is, what is the difference between the heads that take a tapered seat versus the heads that take a washer'd spark plug. My experience with Chevy engines has been with tapered spark plugs. __________________ -Scott- Last edited by sjarrett71; 12-01-2012 at 12:06 AM.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.