383 stroker which spark plugs?

[labbetheking]

Sorry for not being so active in here but i really need your help.
I've tried to search for an answer online but i'm having a hard time to .

Just about to start up my new engine.. pulled the spark plugs and run
the starter until i had good oil pressure.
When i pulled the spark plugs i saw i had some champion RC14YC ? (leftover from another car i had).

I'm thinking they are way to hot for my engine. (specs: 383 stroker, trick flow 195cc heads, pro flo 4 efi, comp 10,7:1 not 100% tho).

Which NGK spark plugs should i go for?

 

[Ricko1966]

Spark plugs need to match the thread depth of your heads. Get 1 number cooler than a 350 chevy if they don't foul all is good if they foul,make sure af ratio is good ,no oil consumption problems,if no bump up one heat range.

 

[labbetheking]

Thread depth is 17,5mm and i ran those spark plugs on a chevy 350 with the same heads i have now without any problems.
Guess i'll order some colder ones and take it from there.

Thanks!

 

[Rustisbest]

NGK BKR6E

 

[labbetheking]

Ok i'll check them out

 

[Ricko1966]

You want to run the coolest plugs you can get away with. Meaning good drivabilty and no fouling. A hotter plug does not mean a hotter spark it means the plug retains more heat to prevent fouling. The hotter plug is more susceptible to preignition as a hotspot. The cooler plug allows a denser AF charge and possibly more ignition lead. That's why I start cold and work my way up as needed.

 

[Grit dog]

NGK BKR6E

That’s pretty hot, no?

 

[Rustisbest]

That’s pretty hot, no?

NGK numbering is backwards. 5 heat range is around stock. 6 is one step colder since its a 383 with 10.7 to 1 compression according to him.
I run the 6 in both my Tahoe with the AFR eliminators and the Blueprint crate in the C10. Also if you add a -11 to the end of the part # it gets you a .045 gap as apposed to a .035 = BKR6E-11.

 

[Rustisbest]

Heres the paperwork that came from Blueprint. Same as what AFR recommended to start with. Dont have that paperwork anymore since its been 13 years ago

You must be registered for see images attach

 

[Grit dog]

Interesting. I know NGK numbers are backwards for heat range. I thought 5-6 was hot, 7-8 mid range and 9-10 cool.
Good to know. Thanks.