I am also currectly running copper Motorcrafts but when I increase the Boost to 14PSI on my Kenne Bell I Want the Denso Iridiums in there.
I already have a set of one step colder waiting to be installed!!

I'm gonna try one more time.lol

Will they do anything better to my "N/A" Mach1? Thanks.:)

I had Standard heat range ones in my 4.6 2V when it was N/A and the pedal response was better and fuel mileage improved a little.

Thank you very much. I appreciate the response. 2v or 4v probally react the same N/A. Thanks again.

Not Denso, I bought them just after I put the car away. NGK I think... it's been so long.

Not sure what the factory plugs are?

But if I recall from a previous vehicle when I put in platinum plugs I felt a difference so I'm sure there will be a diiference when these go in.

Will let you know. I'll leave the old plugs in for the first week then swap then out.

You'll have to wait till April :cry2:

Heres some more info...:

Testimonials:
http://www.mach1mustang.org/vbulleti...hlight=iridium

Heat ranges:
http://www.accufabracing.com/denso_2.htm
:cheers:

Hey Greg, your car would actually only need a 1 step colder plug because of the efficency of the 4V combustion chamber...you can actually go with too cold of a plug. 2V's and 4V's react very differently because of combustion chamber design. Stick with a 22 heat range plug such as NGK TR6's or AWSFA 22C's, which are great. Autolite also makes great plugs in the 22 heat range. I am happy to help if you have any questions.

On a N/A car I would gap them at .050 and a blower car I would gap them between .030 and .035 and on higher boost car's (500+ rwhp) between .026-.028

What is a colder plug for a 90 5.0? I am using NGK UR55. I assume these are 1 range colder than stock.