Hey all,
I'm working on getting my kit installed and wondering what plug I should go with. Br7 or br8?
I plan to run a progressive 200 on a 102mm plate. I run around 25 degrees timing na with worked 243 heads. Probably start with 15 on the bottle. I'll be working my way up to the 200 starting at 100 to make sure everything is looking good.

The motor is a ls3 based 418 with 11.5:1 cr on 93 pump. Cam is a Texas giant with 112lsa. About 22 degrees of overlap if I remember correctly.

What plug should I look at using?

 

I'm thinking you're right at that definitive line between the two plugs. Have you called your nitrous company and asked them?

 

Bought a used nitrous outlet kit. Looking for opinions. How different would the car run na with an 8? Can I adjust the tune? Better to be safer with a colder plug right?

 

Im in the same boat and have 2 days to decide as the cars getting dyno tuned on spray Thursday morning .

 

For the 200HP I'd start with the 8's and go to the 7's if the 8's aren't showing any heat on them. 200HP is one of the points in the HP range where it could be the 7 or 8, and it's always safer to start on a colder plug than to have to hot of a plug and melt them down. For the 150HP shot, the NGK BR7EF would work great-

 

I run 8's and only thing I noticed was it took a little longer to idle on the first start. Till they got some heat in. Maybe about 2 minutes then was good to go.