Just did my spark plugs. I did a lot of searching to find the right replacements. I ended up buying NGK PMR8B. P=platinum M= hex size R=resistor type 8=temperature and B= double platinum. Early cars had PMR8A where the A= single platinum. Anyway the B version is what is currently available. In fact, when I pulled my plugs my car had the B version already. The manual listed an NGK plug which isn't made anymore. The PMR8B have the correct gap. With the PMR8B the gap is preset, so as long as the tips havent been dropped and bent you don't have to gap. My old plugs had 59K miles on them. The gap was off (larger). The engine runs better with the new plugs! (Also changed the cam cover gaskets. No more smell of buring oil)
59K Miles with the same spark plugs, that's impressive! Good job I ordered mine at a very good price and should receive them in a couple of days. But I didn't dare to wait that long before changing them as my car has "only" 27K Miles BTW, the 360, 430 and several Maserati models (quattroporte,spyder and coupe 4.2) use all the same NGK PMR8B plugs.
Yeah good plugs if anyone needs them we have them instock. I put these in my car when I changed the clutch earlier this year. $13.99 each x8.
The PMR8B has platinum on both the ground and electrode, so they should last a while. 60K miles is my guess.
60K miles is very good for a spark plug. To be a bit more complete about the PMR8B signification, may I add this : M for 10mm thread, 16mm tool. 8 for heat rating, 2 coolest, 12 hottests.
