[Marc F.]

For 21 years I did specialized metal casting. Copper is relatively easy to melt. I had to cast platinum, its melting point is about 3220 degree F. I think. I can see that making the plugs last longer. Each time its fired a fractional amount of metal is erroded by the very hot spark.

I have no idea about irdium. Also the alloys make each metal behave differently.

Metallurgy has advanced quickly from when my car was built to now (1982). The original engineers didnt know about the plugs we have now. But as its pointed out profit is involved too. While we can afford more $ per plug for a better product if you multiply that by 300,000 units yearly it makes sense to use a cheaper plug if it does a good job.

I can't agree that only using a manufactures recommended plug is the only way to go. We are modifying our engines/cars and running them in ways never even concieved by the original engineers. Learning to read the plugs like hot rodders do is what I would do. The original may be the best choice but it may be the wrong heat range after you tweak everything else on the engine.

By the way I chose the OEM recommended spark plugs, money was a concern. But with some of the engine mods I may have to change them.

I have noticed a trend in various threads to state "this is the only way to...you have no idea what your talking about, etc, etc". The problem is that our personal way of driving, modding, and where live is never considered. I am trying to add to information, not tell anybody they are wrong.