spark plug question?

ok,ive read a few threads with different answers.i couldnt find autolite 104 copper plugs anywhere in town(autozone etc etc) but i found some ap104 autolites(platinum) is that ok for when i go to the 3.4 pulley? is there a huge difference between platinum and copper? if its gonna cause problems down the road ill take them back and order coppers online,just wanted to ask,thanks.

The only difference is price. The reason many modders use non-platinum is because they are cheaper and many check/replace their plugs often for optimum performance. The AP104's will perform just like the 104's, they're just more expensive, so you're good to go when you get the new pulley.

ok thanks for the info ,not expensive though i got a whole set of them for $10 at wal-mart,guess i got a good deal.

Have you tried Walmart? Why are you using Autolite 104s at this point in time? For 3.4" SC pulley upgrade one range colder should suffice which would be AL 605. After mods then run a scan for KR (knock retard). You don't want to run too cold spark plugs. Also, be sure to adjust the gap to less than the stock .060" with the copper core.

AL606 - Stock
AL605 - One range colder
AL104 - Two range colder
AL103 - Three range colder

You can use the AL single platinum (AP) but the cooper cores are made so you can vary the gap without any issues and for overall performance a better spark plug based on design for performance applications.

i plan to scan :iceslolan ,also the reason for 104's is im getting headers and other things first,and if im ok on knock ill be dropping to a 3.3,and i dont wanna have to change plugs more than once to soon.

The headers will take care of any possible KR based on your mods so that would not be the reason to go to 104s since headers reduce or contain KR. You should scan for KR before modding so you get an idea what is is now before mods. 104s are good for SC pulleys smaller than 3.3" like 3.25" which is more common to use over a 3.3". I run a 3.0" with AL copper core 103s but my mods both intake and exhaust fully support the use of that size SC pulley. Plus I run an S Ported M90 blower.

Note: The Autolite AP single platinum plugs are only good for up to 50K miles if you are lucky. If you wanted longevity then the APP double platinum are a better choice since they are good for up to 100K miles.

i thank you for all the info,and i know that you own these cars and have had them longer than me,but i didnt ask you to criticise my setup or to tell me what to run,ive seen countless numbers of ppl running 104's with a 3.4 almost everyone does,you have your opinion i have my read up on opinion ,thanks for the help but not all the criticism.

i thank you for all the info,and i know that you own these cars and have had them longer than me,but i didnt ask you to criticise my setup or to tell me what to run,ive seen countless numbers of ppl running 104's with a 3.4 almost everyone does,you have your opinion i have my read up on opinion ,thanks for the help but not all the criticism.

To start when you post an issue or question related to spark plugs you will get varying suggestions or opinions to include criticism which may also be constructive in nature or on the flip side of the argument. It is your car and you can do what you please with it. All I'm doing is passing on my knowledge, wisdom and experience which you can take for what it is worth. If you don't like it or accept it no skin off my hide but I'm entitled to my opinions. Keep in mind this is a discussion forum and members are allowed to weigh-in once you post the issue or question.

The issue in your case is not whether it is OK to use the Autolite 104 heat range plugs based on your mods but whether you made the right purchasing decision and/or bought the right spark plug. The recommendation to use colder Autolite spark plugs in a modded GTP is based on solely the "copper core" design and not the single (AP) or double (APP) platinum versions. There is a difference between them and you have to be careful with platinum or iridium electrode plugs since part of the recommendation is to adjust the gap accordingly based on your mods before installation. Not even ZZP recommends using colder range Autolite AP/APP platinum spark plugs. The recommendation is "copper core" only. People that think they are the same design, OK to use, and/or follow the same heat range progression or there may be no issues using them are clearly misinformed.


You answered your own question in your original post.

if its gonna cause problems down the road ill take them back and order coppers online,just wanted to ask,thanks.

Not even ZZP recommends using colder range Autolite AP/APP platinum spark plugs. The recommendation is "copper core" only. People that think they are the same design, OK to use, and/or follow the same heat range progression or there may be no issues using them are clearly misinformed.

Bob am I causing damage running AP605's instead of Copper Core 605's? Wally world didnt have 605's, but did have ap 605's which is why I went with them. Should I change them out?

To the OP, Not sure if it has been mentioned, but running a spark plug thats "too cold" might not cause compltete combutsion and ultimatly foul out causing a miss-fire and starting issues. Why do you think at eh factory they put in delco 41-101 which is equivelant to an APP-606? If a colder plug could be ran safely without issues, dont you think they would be installed right off the line?

Also, no one is criticizing your opinions. We are just stating ours based on past experiences.

Also I should mention.... I installed a 3.5" pulley, 180 stat, and autolite 605's all at the same time. After I installed the 605's my car didnt seem to start as quick as it used to. Before when I had delco 41-101's in, all I had to do is tap the key and it would turn over and fire. Now its almost a second or so of cranking before it turns over and runs. (I'm thinking maybe because of the plug change) Just FYI.

Bob am I causing damage running AP605's instead of Copper Core 605's? Wally world didnt have 605's, but did have ap 605's which is why I went with them. Should I change them out?

Hard to say Tim. What gap are you running?

I'm still trying to figure out how good sound discussions here and at other GP forums about which Autolite spark plugs to use as an alternative got side tracked or convoluted and the AP/APP platinums wound up in the picture. :screwy:

All I can say is I have never used the Autolite AP or APP platinums in my GTP. I went with the AL copper core as originally suggested way back when. They are still available depending on the supplier and obviously Wally World is not the place to get them anymore.

I cant quite remember what I gapped them to. .60 thousandths I think. I've been running them sinch may, and I think I will swap them out again in spring.

what about a range colder delco plat plug? If I put them in would I be good for 50,000?

I cant quite remember what I gapped them to. .60 thousandths I think. I've been running them sinch may, and I think I will swap them out again in spring.

what about a range colder delco plat plug? If I put them in would I be good for 50,000?

With your mods the gap should be around .055". Why not just use the copper core? I contacted 3 Autozones within 3 miles of my location out of 20 stores and there were plenty of Autolite 605 and 104 copper cores in stock. $1.73 each.

Anyways, in AC Delco double platinum which is a 100K mile plug:

1 colder.......41-932


In iridium 100K mile:

1 colder.......41-985

Note: When you gap the Delco platinum/iridium plugs make sure the electrodes are aligned properly and the tit doesn't break off.

same .55 thousandths gap for delco plats?

i went to autozone and advance auto yesterday,neither had copper core plugs,i think there just stupid and have them but are trying to sell more expensive plugs,only plugs they SAY they have that are copper and right for my car are shitty bosch plugs,ill stick to what i have if they cause problems ill order some coppers from zzp and switch them out,thanks again for yalls info. oh and should my gap be .055 with a 3.4

dont tell them the application. Just walk in there and say you need 6 autolite 104 spark plugs. They will never find it if they are looking it up for a GP.

ill have to wait till i get paid,ill try the just asking and see what i get,i saw today i need an inspection so thats my money for now.

yep, fun inspection time again! I'm lucky, in MN we dont need them. But my car would pass anyway.

Just had a thought, could you order plugs off line and have them shipped to your stor for free? Cause I'm sure you can find what you need on advance.com

You can go instore also to order the parts as long that you have the part number. I did that at murrays discount auto parts.