What spark plugs for Eldorado 1979?

[T.Skytte]

Hi all,

What plugs would you choose?
I think I might prefer ACDelco just because that was probably original, right?
So I think some sites suggest R45XLS6
These are very cheap though, which is great  , however I don't mind paying more if I also get something out of it (better burn, fuel economy, last longer, etc).
It's not a racing car so.. also don't want to overspend on this.
In this case what would you recommend?

Thanks a lot as always.

TS

[T.Skytte]

By the way this is the 5.7L  EFI motor..

[TJ Hopland]

Good to hear you don't have the diesel (the only other option that year), those are hard to put spark plugs in.

I think I would just stick with the OE's.  I'm not a believer in any of the fancy v or x or whatever plugs.  Same with stuff like platinum in older engines.   I have read in some cases those are worse because the surface area is so small they can suffer from build ups which then causes problems when compared to a standard plug where the spark just moves to a clean spot.   Its not a problem with newer EFI stuff because they are just tighter more controlled engines to start with. 

[T.Skytte]

Hi TJ and thanks for your reply!

yes no diesel.. hehe  .. It's "the one with the good engine"... 
Interesting that platinum might actually be worse.  I also ready that just about the only advantage to platinum is that they last longer. Since changing the plugs is relatively easy I think I will stick to the regular ones as you suggest.

For others note: I  researched some more and it seems other sites say ACDelco R46SZ is compatible and the previously mentioned R45XLS6 is NOT.  So caveat emptor.

[bcroe]

Don't laugh too much at the diesel.  That option made my
car exempt from emissions testing (what a relief).  LOTS of
extra duty stuff included.  Then when the diesel quits you
can drop in any engine you please, no computers to worry
about, no testing.  I have picked up more than one very
nice diesel car for a song, then swapped out any faulty parts
over the weekend.  There are 3 of them here now. 

My 79 Eldo has a 6.6L, but that requires a retuned ECU. 
Bruce Roe

[35-709]

The Platinums in my '71 472 have given excellent, long-lasting service.  I will try Iridiums next if I can just wear out the Platinums.

[TJ Hopland]

A nice tight engine I would think they would be fine, it seems to be the average well used engine that may have issues.     The way most of us drive the older cars the change interval isn't really a factor not to mention most of the time they are really easy to change compared to newer designs.