Hey guys I have been doing some research on what plugs to buy for my #906 vortec heads and I came across some issues. I have been using Autolites for a while but I read that I need special plugs which require a special length (.708"). I've been using regular plugs and this could be why I've had some power issues. I bought some long plugs for a vortec v8 and the mechanic said those are too long and they would clap my pistons. Looking at my dads vortec tahoe it appears that theres a spacer for the plugs or something to accomodate that extra gap? Also what would be the best gap for my setup

 

i use the champion 13, 0r rs14yc6

 

http://www.summitracing.com/parts/FR...n/?prefilter=0

Says that these AR103s fit but i'm worried about the gap. I dont want to destroy a motor over spark plugs lol

 

that plug is colder. its also shorter and should clear headers better. either one will work. i might switch to these ar103 myself.

 

Does that size go by the length of the back side of the plug where the wire goes into it or the front where it threads into the head? Because i remember very well asking for 96' chevy 1500 spark plugs since theyre vortec and getting long threaded spark plugs.

 

Just go to any Gm dealership and get the Ac Delco Platnum plugs for vortec heads. They work great but can be costly. I ran standard plugs in my vortec heads till I found there was a difference, big power issues at high rpm. Now the engine runs stronger then ever with the right plugs in.

 

Its the threads that are longer not the plug. Vortec plugs have more threads then a normal sbc plug letting it travel farther into the cumbustion chamber.

 

the autolite racing plugs are shorter on the exposed portion which is good for header clearance. the colder heat range will help with your higher compression ratio which is the same as mine. i'm eventually changing out to the ar103 myself. i get some slight pre-ignition under heavy load with the hotter #13 plugs so i retard my timing a little and kill some ponies.

 

Man maybe thats been my problem the whole time is that my plugs were too short. I'm only running 13.89s with my vortec setup trapping 100 when i should be trapping 105ish. Can you get me a part #? thanks alot man, how much difference did you feel?

 

Yup that is your problem,

like i said before at high rpm with my old plugs in my engine would miss or dog out. my first run at the track I ran a 14.22@91mph. I had to keep letting off. I havent been back to the track yet since i put new plugs in but the snow finally melted here and the ground is drying out so it should be any day now. You will defintley be able to tell that the old plugs were your problem once you get the new ones in. Let us know how it goes!

 

what's the part number on the plugs you've been using? when i first put vortec heads on my car about 10 years ago i tried to reuse my r44t plugs and the car wouldn't start.

 

Ill get you the part # as im on my way back to work now.

 

Bought some AR103s installed 2 of them and no problems, having a shop do the other 6 because im too lazy to get around the headers lol, thanks guys

 

Will do man we have a very similar setup, this shop is also installing new magnum rocker arms, adjusting valves checking carb timing and everything. They're a pure drag racing shop so they should hook me up pretty good. I will keep ya posted

 

I am using Delco 993s. Are those correct or should I change out also?

 

The delco plug part # for vortec heads is #12607234. The 993's are also a good choice for Vortec heads but the ones I listed are platnium and are gauranteed for 100k and dont have to be gapped so they say. The 993's are just a standard plug made to fit the Vortecs.