Hi Guys,

I am just vwondering has anyone got any suggestions on best spark plugs for AU XR8 with mods. Mods are GT40X heads, DiFillipo headers, and screamin demon coil paks. I currently have the NGK Iridium's but according to screamin demon the plug gap can be widened to 0.065" (1.65mm). Apparently you can't re-gap iridiums, so i am thinking of Autolite dble platinums.

Looking at their aussie chart, there are different few part no's for AU XR8/TS50, which is strange as they are the same engine (alloy head may have something to do with it).

Part# as follows:

AU XR8 S1/2/3 - APP605 Heat - F14 (large gap)
TS50 200kw - APP104 Heat - F14
TS50 220kw - APP3923 Heat - F11
TS50 250kw (5.6L) - APP103 Heat - F14

so you can see the difference is essentially the same engine. Should I consider that my heads are the alloys (not std AU XR8). Also is it worthwhile considering heat ranges.

cheers

Ive regaped the iridiums in my Clevo when I added the Crane ignition they were fine I think they say not to as they are very easy to stuff up.