Thought we would contribute our detailed spark plug reference to the site. We spent a lot of time putting this together, hopefully it'll aide you guys in your spark plug selection. Its not going to tell you what to choose, but rather part numbers for what you can run and equivalent of NGK plugs. We made this awhile ago but didn't post it since we found our last one on other peoples sites. But we figured it would be really useful to you guys.

It was tough to format it for this site, so just let me know if you have any questions about this, plug selection or anything else in general.


Gasket Seat - .708 - .75" reach - 14mm thread dia. - 5/8 hex
Fittment - LSx & LTx w/ gasket seat plugs

Non-Projected tip "gasket seat" plugs that are in bold are highly recommended for nitrous applications!

#Heat Range [Brand] [Part Number] [Design Number] [Tip Designation] [Special Notes]

#5 [NGK] [7373] [FR5] [Projected Stock Heat Range.]
#5 [NGK] [6130] [BCPR5ES] [Projected Stock Heat Range.] [Tighter Gap.]
#5 [NGK] [BKR5EIX-11] [Projected Stock Heat Range.] [Extended Gap.] [IRIDIUM]
#5 [Denso] [3137] [Q16PR-U] [Projected Stock Heat Range.]
#5 [Denso] [5305] [IK-16] [Projected Stock Heat Range.] [IRIDIUM.]
#5 [Champion] [431] [RC14YC] [Projected Stock Heat Range.]
#5 [Autolite] [5503] [5503] [Projected Stock Heat Range.]
#6 [NGK] [2330] [BCPR6ES] [Projected] [1 step colder w/ projected tip.]
#6 [NGK] [6418] [BKR6EIX] [Projected] [1 step colder w/ projected tip. IRIDIUM.]
#6 [Denso] [3007] [Q20PR-U] [Projected] 1 step colder w/ projected tip.]
#6 [Denso] [5304] [IK-20] [Projected] [1 step colder w/ projected tip. IRIDIUM.]
#6 [Champion] [344] [RC9YC] [Projected] [1 step colder w/ projected tip.]
#7 [NGK] [4091] [R5671A-7] [Non-Projected] [2 steps colder w/ NON-projected tip. Non-Resisted.]
#7 [Denso] [3010] [Q22PR-U] [Projected] [2 steps colder w/ projected tip.]
#7 [Denso] [5310] [IK-22] [Projected] [2 steps colder w/ projected tip. IRIDIUM.]
#7 [Champion] [284] [S65YC] [Projected][/b] [2 steps colder w/ projected tip. Non-Resisted.]
#7 [Autolite] [3922] [3922] [Projected] [2 steps colder w/ projected tip.]
#7 [Autolite] [AR3935] [AR3935] [Non-Projected] [2 steps colder w/ NON-projected tip. Non-Resisted.]
#8 [NGK] [4554] [R5671A-8] [Non-Projected] [3 steps colder w/ NON-projected tip. Non-Resisted.]
#8 [Denso] [5311] [IK-24] [Projected] [3 steps colder w/ projected tip. IRIDIUM.]
#8 [Champion] [796] [C63YC] [Projected] [3 steps colder w/ projected tip. [Non-Resisted.]
#8 [Champion] [279] [C63Y] [Projected] [3 steps colder w/ projected tip. Non-Resisted. Cut back electrode.]
#8 [Champion] [298] [C63CX] [Non-Projected] [3 steps colder w/ NON-projected tip. Non-Resisted. Cut back electrode.]
#8 [Autolite] [AR3934] [AR3934] [Non-Projected] [3 steps colder w/ NON-projected tip. Non-Resisted.]
#8 [Brisk] [D12S] [Non-Projected] [3 steps colder w/ NON-projected tip. Non-Resisted. Cut back electrode.]
#9 [NGK] [5238] [R5671A-9] [Non-Projected] [4 steps colder w/ NON-projected tip. Non-Resisted.]
#9 [Denso] [5312] [IK-27] [Projected] [4 steps colder w/ projected tip. IRIDIUM.]
#9 [Champion] [794] [C61YC] [Projected] [4 steps colder w/ projected tip. Non-Resisted.]
#9 [Champion] [785] [C61C] [Non-Projected] [4 steps colder w/ NON-projected tip. Non-Resisted.]
#9 [Champion] [278] [C61Y] [Projected] [4 steps colder w/ projected tip. Non-Resisted. Fine Wire. Cut back electrode.]
#9 [Champion] [688] [C61] [Non-Projected] [4 steps colder w/ NON-projected tip. Non-Resisted. Fine Wire.]
#9 [Champion] [297] [C61CX] [Non-Projected] [4 steps colder w/ NON-projected tip. Non-Resisted.] [Cut back electrode.]
#9 [Autolite] [AR3933] [AR3933] [Non-Projected] [4 steps colder w/ NON-projected tip. Non-Resisted.]
#9 [Brisk] [D10S] [Non-Projected] [4 steps colder w/ NON-projected tip. Non-Resisted. Cut back electrode.]
#10 [NGK] [5820] [R5671A-10] [Non-Projected] [5 steps colder w/ NON-projected tip. Non-Resisted.]
#10 [Denso] [5321] [IK-31] [Projected] [5 steps colder w/ projected tip. IRIDIUM.]
#10 [Champion] [792] [C59YC] [Projected] [5 steps colder w/ projected tip. Non-Resisted.]
#10 [Champion] [277] [C59Y] [Projected] [5 steps colder w/ projected tip. Non-Resisted. Fine Wire. Cut back electrode.]
#10 [Champion] [687] [C59] [Non-Projected] [5 steps colder w/ NON-projected tip. Non-Resisted. Fine Wire.]
#10 [Champion] [296] [C59CX] [Non-Projected] [5 steps colder w/ NON-projected tip. Non-Resisted. Cut back electrode.]
#10 [Autolite] [AR3932] [AR3932] [Non-Projected] [5 steps colder w/ NON-projected tip. Non-Resisted.]
#10 [Brisk] [D08S] [Non-Projected] [5 steps colder w/ NON-projected tip. Non-Resisted. Cut back electrode.]
#10.5 [Champion] [791] [C57YC] [Projected] [5.5 steps colder w/ projected tip. Non-Resisted.]
#10.5 [Champion] [276] [C57Y] [Projected] [5.5 steps colder w/ projected tip. Non-Resisted. Fine Wire. Cut back electrode.]
#10.5 [Champion] [686] [C57] [Non-Projected] [5.5 steps colder w/ NON-projected tip. Non-Resisted. Fine Wire.]
#10.5 [Champion] [295] [C57CX] [Non-Projected] [5.5 steps colder w/ NON-projected tip. Non-Resisted. Cut back electrode.]
#11 [NGK] [6596] [R5671A-11] [Non-Projected] [6 steps colder w/ NON-projected tip. Non-Resisted.]
#11 [Champion] [693] [C55] [Non-Projected] [6 steps colder w/ NON-projected tip. Non-Resisted. Fine Wire.]
#11 [Champion] [294] [C55CX] [Non-Projected] [6 steps colder w/ NON-projected tip. Non-Resisted. Cut back electrode.]
#11 [Autolite] [AR3931] [AR3931] [Non-Projected] [6 steps colder w/ NON-projected tip. Non-Resisted.]
#11.5 [Champion] [293] [C53CX] [Non-Projected] [6.5 steps colder w/ NON-projected tip. Non-Resisted. Cut back electrode.]

 

This might be an easier to read version.

 

I was really hoping to see you guys introduce a new product in this thread. I was thinking something like a new purge button or something.

 

That needs to be stickied!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

 

thank you for the work involved in putting this together, and will answer a lot of question that get asked at least once a week on here. very nice.

Stickey material

Also it may be a good idea to put in when you should change to the next heat range, as that is a question that gets asked a lot and if put with this chart would be awsome.

 

We can come up with some very general guidelines on plug selection if you guys want. The difficult part is that plug selection does not rely on shot size alone. I can give you a general chart when to go up in heat range based on shot size and compression, but like i said, id rather have you ask me directly with all the specifics on your build. Like i always say though, when in doubt go with a plug colder than you think you may need. You can't hurt your motor going too cold.

 

Def. bookmarked. Thanks guys

I gotta call you guys soon to get some more misc. parts. talk to you in a little.

 

There is also a '7 NGK 3526 BP7EFS Projected 2 steps colder w/ projected tip.' for the Taper Seat - .708.

Probably few cases where this plug is needed but it may save someone the trouble of buying the wrong plug if it were on the list.

 

Sure we can add those and your right it was RARE and pretty much unacceptable to use it on a nitrous application.

 

very nice list. I have it all memorized so you can go a head and delete all the information...
Robert

 

your test is tomorrow, better be ready.

 

Any chance you could give me some 3 step colder options for a 3.8 turbo Buick? The juice is blowing the spark out and the guys on the TB forums are no help.

-Will

 

Yup, got ya covered. Its not a great image but hopefully you can read it. For those that will become confused...THIS IS THE TURBO BUICK SPARK PLUG CHART



Nick

 

If anyone else needs a different vehicle PM me, we have charts for just about all cars.

Nick

 

Much appreciated. Now I need to read up on the advantages/dis of projected vs. non and resisted vs. non.

Thanks again,

-Will

 

I dont see the Autolite AR93's on there tapered seat for the LSx

 

I run AR 3932's in mine. They are equivalent to a NGK11. Non projected tip and washered.

They are a little tougher than the NGK's.

 

TTT. just used it today to make sure I had the right part number. great reference

 

It's amazing what happens when a truly knowledgeable sponsor posts actual technical content in here, instead of the typical "our stuff is best because...ummm.....we say it is."

PS Since I'm in Canada I have to end everything with eh.....eh?

 

Ahahahaha chaaaa chingggg. Lol. Agreed stuff that we all can learn and reference for later use is wonderful. We know this is no marketing just helping out everybody. Ehhhhh......?? Lol