i agree with "IDB" Mike, et al. (sorry Mike, could not resist.)thompsonsd said:
platinum sucks. it is very hard and as a result, does not conduct well compared to copper. think of cheap, really hard rubber tires vs some nice soft Nittos. the hard rubber ones will last forever, but which do you want to autocross in?
platinums are nice for some applications, like Z28's. i lost much skin and hours doing plugs on the 94 camaro, though i did use copper, i can see the need for platinums. it is funny that people remarked that the bosch platinums broke. i found a huge miss in the eclipse last week. came to find that one plug had separated from the body (if i turned the ceramic part, the electrode spun too).
i agree in full with others that while they may be good for 100K in terms of gap erosion, they may break long before that.
on EFI stangs, the side effects of platinums seems to be a low idle and cutting out at or above 4K rpm.
i did not know Autolite made platinum. arent coppers good for 30K (maintenace interval from ford)? i dont leave plugs in for 1/3 that long anyhow. gap them a little tight to help with accomodating gap erosion in they are going to be left in for awhile. also helps with weak ignition.
just my two cents worth.
PS, Mike, i was reading timing chain threads last night. came across one of yours from the Corral a few years ago (when the bolt in the block stripped, etc). how was your chain when you eventually got to it? you did not have a lot of miles on it, as i recall. curious, i have a thread about life of chains going.