Ok i know the normal turbo spark plug is the ngk bcpr7e. my stock plug is ZFR6F-11. so shouldn't i go with an 8? if so is there any plug that's an 8 that stores like kragen/autozone/pepboys stock that i can use for my turbo project. normally i just order them from sparkplugs.com but i got a race 2moro and need them asap.

 

7's are fine. I dont think people use 8's till 500+? or maybe higher.

 

but the general rule of thumb is go 2 steps colder, so does this not apply to preludes?

 

one step colder should work fine, go with the 7's