Spark plugs for stagell heads

[N2BUICK]

I have been using autolite AR472,473.474 plugs.
These have been fouling out during some tuning.(160#injectors)
Do not what to get to hot and detonate. Having a hard time locally getting a cross to some other manufactures
TIA
Austin

 

[Mac in SD]

I used autolite 104's, and they didn't foul with 96-punders. switched over to the equivalent platinum-tips because plug changes with the ATR headers are a PITA. They seem to be doing fine.

 

[Big88]

I have used NGK 5724-10. They are a little hotter than AR472.
In the autolites which is warmer 472 or 474?

 

[N2BUICK]

Thanks Mac,I took some 103 and 104 to the track this evening. I did not use them.I kept the AR 473 in with the two passes I made
88,I think the 474 are hotter.Some say the NGK system is different.
Thanks

 

[TurboDiverArt]

Originally posted by Big88
I have used NGK 5724-10. They are a little hotter than AR472.
In the autolites which is warmer 472 or 474?

Higher number is warmer. I use 472's at the track and 473's when driving to the track. Not that having the 473's in there make them not foul out during the 25 miles to and from the track but I figure they are probably better than the 472's while cruising. One of these days I'll swap them out for 474's on the street.

Champion also makes a race plug. I don't know the number but I know a bunch of people use them. I think they are prone to fouling but are suppose to be an excellent plug. The NGK's are also pretty good from what people tell me. I use the autolite plug cause you can order them through Jegs.

What's the Autolite 104 plug? How does it differ from the 472's besides slightly hotter?

 

[N2BUICK]

Art,the 103 and 104 plugs differ in that the 473 type is a race plug they say.
The 473 have a cut back ground electrode and are plated with ?nickel?
They are just a heavier built plug,plus 3 times the cost!
Austin

 

[TurboDiverArt]

Originally posted by N2BUICK
Art,the 103 and 104 plugs differ in that the 473 type is a race plug they say.
The 473 have a cut back ground electrode and are plated with ?nickel?
They are just a heavier built plug,plus 3 times the cost!
Austin

Thanks for the into. Did a search and they are about 1/2 the price of the race plugs. Advanced has them at about $2.29 a plug and Jegs sells the 472's at about $4.50 a plug. Certainly something to keep in mind if I need plugs at a local auto parts store.

Thanks for the info!