Hey guys, strange one.

I ordered a new set of plugs the other day, ive got NGK ones at the minute but decided to go back to Champions.

anyway i checked the part number on RockAuto and it said i needed RC14YC plugs for m 87, so i found somewhere here in the UK that had them in stock, it even stated they were for 87-88 chevrolet on the listing.

When comparing it to my old plug though i couldnt help notice its a bit longer, and has a load more threads

I did try the plug in and it threads in no problem, but i didnt tighten it up, i was worried if its too long it might damage internal parts of the engine if i fire it up

Or am i just being paranoid ?

 

Don't use the Champion plugs you have. They're just wrong; wrong seat (tapered vs. gasket) and wrong reach (thread length).

Double check the Rock Auto parts list. The Champion RC14YC isn't listed.

Edit: I just noticed a thread where you did an engine swap. So the heads that are on your engine now will determine whether you use taper seat of gasket seat plugs.

There is not enough info provide in this thread to determine which plugs are correct.

You'll need to look at the spark plug holes in the heads to determine which type of plugs the heads require (taper or gasket) and then go from there.

I do know that cast iron Chevrolet heads did not use as long a reach plug as the Champions that are in your photo.

 

Damn, well they are just the stock heads, and its an 87 engine the same as my old one, just ive went from a 5.0 to a 5.7

 

First plug that came up



But yeah they dont look right anyway

 

Then you'll need the equivalent of an ACDelco R43TS.

Edit: Read the note for the Champion plug. It says it's for ALUMINUM heads. Your stock heads are cast iron, yes?

 

Ive just been on the actual Champion website and selected my exact car, and its came back with these plugs too, what the hell

 

ah, well there lies the problem. How do you get Aluminum heads if they all had cast iron heads from the factory ?

 

If it's a factory cast iron head of that vintage, you need plugs that look like what you took out. Something's whacked in the x-reference.

Autolite 24 will get the job done in just about any factory cast iron head. They're my go-to plugs. They fit (even with most headers due to their semi-shorty design), they work, they last a good long time, they're available anywhere and you can't argue with the price.

 

The problem is you need to read the catalog a bit more thoroughly.

Corvettes came with aluminum heads. Why it would show up in a catalog for a Firebird is anyone's guess.

 

Weird. Well the place i got them from is swapping them for me, for a set of Champion RV17YC which are the right ones ! i went back through my old invoices for the 5.0 engine when i changed the plugs and thats the ones i had then, and its what some other people i know use in their 5.7's