I posted this on the 6-66 forum but getting no responses, trying here.
I've seen a lot of references here on the forum pertaining to my question, but I don't see any definitive answer. Lots of respect for all the knowledge here, so I'm sure someone on here can dig a little deeper. Here's my issue, I have a 65 Chevy Truck with a 230 engine 1bbl, my manual says it requires an "AC 46N" spark plug, which they don't make anymore that I can find. The part stores (AutoZone & Orielly's) show lots of plugs that cross reference but they all have a thread length 3/4" whereas the AC 46N has a ~3/8", how can that be??? I must say I have been running the 3/4" spark Plug Autolite 66, for some years. I don't see any signs of damage on them but still, it's not the OEM recommended plug. I do see on Jim Carter truck parts as having a picture of a R45 (SKU# ME550) as fitting my truck which has a 3/8" thread, so that agrees with my manual, but Orielly's indicates that same R45 plug will not fit my truck. I see this a lot when comparing spark plugs between part stores, so you see why I'm confused. I have reviewed the site mentioned here in the forum (
www.sparkplug-crossreference.com) but it leaves questions as well. Can someone tell me how a 3/4' thread vs 3/8" thread could possibly work in my 230 6 cyl.? and what plug is available as a correct fit for my engine? To know what plug everyone else is using in their 230 engines would also add some confidence to my selection. Thanks, looking forward to the responses.
