4.3 spark plugs

[Gary H NC]

I picked up some new spark plugs for my 87 4.3 omc,The napa book called for AC platinum # 10
They were like 12 bucks apiece but i got a sister who works at napa's wharehouse,cost me 16 bucks for all 6
Anyone use these before?

 

[cobra 3.0]

Re: 4.3 spark plugs

Never tried them myself. Why platinum? AC-MR43T gapped at .035 is all you need. $16.00 is really cheap though for platinums.

 

[Scaaty]

Re: 4.3 spark plugs

You don't need Plats, you even don't need Marine (the "M" in AC MR43T). I have a 350 that I have regular R43T's in, and it has been run with them since 1977. I don't have a habit of splashing saltwater on them, so I see no reason for the corrosion resistance (only on the outside plug body anyway), and have had NO problem for 29 years, so if you want proof, ya just got slapped upside the head with it. In fact, bought a new set yesterday...$16 + tax for 8...nuff said. Ya wanna toss money away, I'll get ya my address!

 

[Purduebarry]

Re: 4.3 spark plugs

For older GM engines straight AC Delco's are just better. Everytime I've tried something fancy it just doesn't run right. Maybe at first they do, but soon enough they crap out. Newer motors maybe...but for me straight AC's are best! The only difference for the "M" is stainless. If you are running in salt water and are worried about it, use the M, otherwise use straight plugs!

 

[KaGee]

Re: 4.3 spark plugs

Gary, stick with what the factory designed as has been said. In this case, it's cheaper.