ATTENTION: This applies to Vortec and some aftermarket heads only not to "stock" heads.

I posted my situation you can read it (UPDATE on Stealth Ram performance issues)HERE . So I thought I would post a few pictures of what the WRONG and RIGHT spark plugs look like in the combustion chamber (difference between an ACDelco R45TS(taper seat) and R42LTS(long taper seat)). This will hopefully show you the difference between the proper and the old "stand by" plugs.

The first pic is the correct plug, the second is the incorrect plug and the third is both.

 

I missed the first post, so thanks for the follow up.
Ron

 

Thats quite a difference. I was unaware of the plug difference and I ran CR43T's or whatever the stock swirl port plugs are for a month or so with my vortec heads. Honestly it didn't run bad at all, just had some weird surging and wasn't real smooth revving. Live and learn I suppose.

 

Great follow up with the pics

 

This doesn't really have anything to do with this board, but thank you for the info.

 

I was just wondering if this would apply to 081 tpi heads as well because they have the similar step in for the sparkplug as the vortec style heads.

 

Gee I dunno, I have vortec heads on my 3rd gen.....I'd also like to say for the info.

 

I would like to add that the reverse is even worse. I get stuck fixing other peoples' screw ups and when a LTS plug is used on a standard head it makes an even bigger mess. I've run into it on V6s at work. They get the year model wrong, that's all.
Here's what happens: The excesss plug length extends into the combustion chamber and the 3 exposed threads become choked with carbon. When the sparkplugs are removed later the carbon tears the threads out of the heads.
Every freakin' hole.
It's hard to tell which head is which with the valve cover on the head.
Old quote: measure twice, cut once....

 

Went back and checked mine. Guess what, they were wrong also.
Thanks,
Ron

 

I run NGK TR-55's.

 

Over 10 years later and this thread is still saving lives. Recently acquired an 87 9C1 Caprice with some motor work (vortec heads) Pulled the plugs and the PO had Bosch plugs for the original heads installed - way too short. Switched to TR-55’s and my surging at 3500+RPM went away.

Attaching pics of long reach plugs vs originals + picture of thread count on head.

 

I'm glad I'm not the only person who has made this mistake. Thank you for documenting this and actually showing what the difference would look like in the chamber. Believe it or not, there are a LOT of people who are going to look at this thread and find this information extremely helpful.

Edit: just saw how old this thread is. My bad!

 

I bought an 89 Camaro with vortec heads and I am sure it has the wrong small plugs. (thanks to this old thread!)

Did you feel a difference when you swapped the plugs to the correct ones?

 

I would say so. I made a lot of tuning changes between the wrong seat/tip plug to the correct seat/tip plugs, so I don't have an apples to apples comparison. Overall, it just ran better. Running with the wrong plugs made the engine feel very lazy.

This might be a good thread to discuss projected and non projected tip styles as well. Highly recommend projected tips for a better burn, and less likelihood of preignition from a hot tip on a N/A setup. After I removed the tapered seat plugs, I put in some NGK plugs that were the correct reach/seal, but a non-projected tip. Ran much better, but still left much to be desired. Went to the projected tips, and it really runs strong now.