crate plugs

[leafsovrbrs]

whats the plug of choise out there for a 604 --herd something about a marine plug?

[brad hibbard]

we have used the same plug for a very long time
we have tested anything anyone ever suggested and at any gap and have always returned to
NGK R5724-8

we are kinda fussy about the gap and how it is gapped but this plug has served our customers well
here is a link to our recommendation for gapping

http://race-1.com/p-26201-what-should-my-spark-plug-gap-be.html

Brad

https://www.race-1.com

[leafsovrbrs]

thanks brad for everything you do for us racing folks

[brad hibbard]

just throwing this back to the top for some change in conversation-----
I am very interested in what folks are using

I am willing to try anything---what do you use????

Brad

https://www.race-1.com

[GRT62]

Autolite AR103

[CCHIEF]

Splitfire, good for 20 invisible horses!

[over4T]

NGK R5274-9 in our built steel Super Stock engines, gapped to .044. Used these for years and they've been good to us. The spark plug article in the July issue of Speedway Illustrated was interesting and pretty much confirmed what I'd believed for years about all the "miracle" plugs.

[over4T]

Plug number in the above post got transposed...me or computer, don't know. Should be NGK 5724-9. Better late than never.

[brad hibbard]

I think you were correct the first time over4T
NGK does not show a 5724-9 it is R5724-9

my question is how are you getting the gap to .044
the plug is factory gapped under .025 and we manipulate the ground to get it to .037 and keep it straight----I don't see how you can get that much gap and stay straight to the electrode

Brad

https://www.race-1.com

[over4T]

Sorry Brad, I missed typing in the R this time. It IS R5724-9, also known as stock # 7891 to further clarify. A home made tool that I made probably 30 or more years ago only touches the ground strap, if that makes sense. It looks pretty good and that gap and plug has served us well for 10+ years on my home built engines that range from 355-396 cubes and 11.5-14 to 1 compression. It's rare that our plugs need a change in the prox 40-50 race cycle we run our engines and we run up front. I notice your site shows an NGK and also says a .045 gap is GM recommended for the 602 and 604 so I guess you have found better results with the smaller gap. I don't touch crate engines so wouldn't know about them but thanks for the info you put on 4m.