440 spark plug type

[wyrmrider]

Hope you kept the valves- they are pricey
SIL XB stems on the intakes and Inconel exhausts
both industrial hard chrome
66- no apology- we all learned something valuable do not hesitate to post

 

[Lngbrdz]

Autolite ATL-86

View attachment 670546

86 or 85?

 

[CompSyn]

I believe the old Champion J-11Y crosses over to NGK R5670-5. Non-resister plugs. A Pure Stock racer told me good for compression of 9.8:1 or less. I'm using breaker points so probably fine for me.

 

[kiwigtx]

86 or 85?

Definitely 86