I did a search cause I didn't want to repost a question for the zillionth time.

What would be better on a stock LT1 w/ 8 psi and 100 octane w/ an MSD 6btm?

Autolite 103's?
NGK Tr6?

I was trying to find a particular AC delco LT series plug, but they might not make it anymore.

Steve

 

I have used both plugs and like the Autolite plugs alot better. You can also get away with running NGK 104's.

 

Just an FYI
The TR6 plug is 1 heat range colder and
the 103 plug is 2 heat range colder
the 104 plug is 1 heat range colder

I have had sucess with the TR6 plug with my current set up in the sig but I will go colder to the 103 plug in a few months.

Hope that helps,
Claude