Correct spark plug?

[TonyTM]

Does anyone know the correct plug that should be in a 86 coupe with the aluminum heads. I have been given numerous numbers. A chev dealer says 41-800 platinum, AC-Delco told me I have to stick with 41-629 (gap 35) and can't run a platinum plug. The original is FR3LS. Whats everyone else using for plugs with aluminum heads.

 

[Vettefan87]

Go with the ACdelcos. Just make sure they are gaped right. They usually are but sometimes they are off a tad.

 

[vetteboy86]

I'm finding that AC Delco part # is 41-629. I also see that Bosch Platinum +2 part # 4301, and Bosch Platinum Plus part # 4002 are options.

 

[joshwilson3]

Why are the plugs different than on an 89?

I had gone with AC Delco for my 89. A month later I noticed the nuts on the plugs were all rusted out. I'm changing them out for NGK V-power plugs.

From what I've been told, AC Delco just gets an aftermarket plug maker to make their plugs for them. I know the dark metal they are using on their copper plugs that rusted out on mine looks like the same stuff Autolite uses for their plugs. The original plugs are made of a lighter colored metal that doesn't rust.