Any reason why? He has an L67 that is modded, and he plans to continue modding- including a pulley size drop; which means he will want all the KR reducing mods he can. Going to a copper plug will help with that; and Autolite has been more than proven in the 3800 world as a reliable copper plug.

RFI from plugs and wires causing the engine to miss and not shift right? I dunno; if he used the copper autolite plugs mentioned- no one has ever had that issue that I've heard of on the 3800's. As for the wires, as long as he got an OEM replacement/quality wire set- that shouldn't cause it either.

Copper is an upgrade to platinum for the L67's (supercharged 3800's) in terms of performance and knock reduction. Sure it used platinum stock- but the KR reducing benefits of copper plugs on these engines are pretty well documented. The only reason OEM didn't go with them- is no one is going to buy a car now a days that requires 10k mile intervals for basic maintenance.

 

you know the irony bumpin in the owners manuel as well as the service senters as well as shops know a car cant go 10k with out maintenence. 3k for oil 10k for break and belt and oil change and air filter. 20-30k if trans and break fluid and power steering and oil change. pluse fuil and air filter and serpintine belt change. it is wiered that most dont think on doing basic things to keep rolling and having fun with there cars and keeping them reliable. i do agre with you 10k is a bit long on doing maintenence

 

Autolite in the Automotive world as a whole has been more than proven to be the perfect plug search the internet NASCAR did endurance and quality checks of the major "Performance" plugs and not one could beat the standard old Coppers not even the Bosches or NGK's



Most modern engines today have a pre determined air gap inside the Spark plugs to help deliver the appropriate amount of spark and reduce RFI now think of it like this most new cars are Transmission controlled spark meaning the two components at some point meet up with one another wrong air gap inside could induce RFI through the harness and send wrong signals to the PCM leading to a miss and wrong shift points, there are TSB's for certain issues like this too

Platinum costs more than Copper if that were true OEM would've cut costs and used a better KR plug instead but then again Feds want a car to do 100K before any emissions devices and components need repairs