Need to have a place to start with the plug temp. I have been told a ngk #7 heat range is a good place to start. Retracted tip is better for keeping away detonation. What are people using? I have afr heads that use a factory type L98 plug. ngk r5671a-7 is a retracted tip race plug that might work.

 

yeah that ngk isn't a bad place to start. i use the -10 right now, which i believe is to cold and i am going to try an 8 next time. but i wanted to start out on the cold side, just incase.


this is not a stock type of plug thou. this is a 3/4 in reach gasket seat plug. i have trickflow heads and they take either style plug, the cone seat or gasket seat but they have to be 3/4 long. you may want to double check what your heads want. cause i think a stock l98 plug is only a 1/2in or less reach. this ngk would be to long if your heads only need a stock depth plug.

 

It takes a ac delco fr5ls or fr4 ngk style plug which is the same for the aluminum L98 head from the vette. I double checked it. I ordered ngk r5671a-7 which is a medium temp retracted tip race plug. A number hotter than what a lot of ford guys use in 700whp and up afr headed combos.

 

oh yeah, forgot about the alum vett heads. was thinking the stock iron l98 heads. yeah my heads call for the fr*ls plugs too. so your good man. just remember ngk numbers its plugs backwards. higher number is a colder plug. but I think u knew that.

 

yeah thanks. You turned me to the $59 stuff and got it ready to go for the car. Now need to finish my cold side stuff. Turned out I have 42 lbs injectors so starting with your file you sent me. Thanks again for that.

 

good deal man... just remember that I have a supercharger and your turbo will make boost in a totally different part of the map. so becarful when in boost. but set the fuel psi at 45 with the vac hose off and it should start and run well under boost. let me know how it goes.

 

yeah I am starting with 5 lbs to start. I remember you saying not tuned in the boost range so will need to keep an eye on the wide band for sure. thanks