Thanks Cliff, using the cross reference chart, it shows the AC R44S plug crosses to a NGK BP5S plug. Oreillys website shows a NGK XR4 plug for a 1970 RA III Trans Am. These are stock Heat Range I suppose, is the stock Heat Range fine for high compression, pump gas engine, or is it better to run a plug a step colder? Now, I have to find out what the difference is between the NGK BP5S and the XR4.
__________________
1978 Trans Am
Pump Gas 461 Stroker
|