What's the correct Spark Plugs? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

SonomaComa · 07-12-2018, 12:24 PM

I have a 1969 C-20 with a stock 350 and it does have HEI. I am replacing the spark plugs and plug wires with some MSD #31239 cut to fit wires.
The plugs I purchased at O'Reilly's are R43, the ones I removed are R43S.
Is that going to make a difference? The only difference I see is that the R43S is a little longer and extends farther into the combustion chamber. What would be the advantage of a longer plug?
The plugs I removed look fine, no oil build up or anything out of the ordinary so I don't think a hotter plug would be necessary...?
The AC Delco website even says the R43 plugs are the correct ones. http://parts-catalog.acdelco.com/cat...log_search.php

07-12-2018, 12:24 PM	#1
SonomaComa Registered User Join Date: Sep 2015 Location: Sonoma County California Posts: 83	What's the correct Spark Plugs? I have a 1969 C-20 with a stock 350 and it does have HEI. I am replacing the spark plugs and plug wires with some MSD #31239 cut to fit wires. The plugs I purchased at O'Reilly's are R43, the ones I removed are R43S. Is that going to make a difference? The only difference I see is that the R43S is a little longer and extends farther into the combustion chamber. What would be the advantage of a longer plug? The plugs I removed look fine, no oil build up or anything out of the ordinary so I don't think a hotter plug would be necessary...? The AC Delco website even says the R43 plugs are the correct ones. http://parts-catalog.acdelco.com/cat...log_search.php



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.