ClassicCar

41truck wrote:

What is a good plug to replace the factory J9 with as J series is hard to find ,with todays fuel is the NGK B6S a good choice? From what I can find out the J9 had a heat range 6 and the J7 heat range 8 Thanks

I always used to run Champion J-7 plugs in my Hudson eights, and you are right that they are hard to come by. I believe Hudson recommended the J-7's in the stepdown eights, at least that is what I see in the owner's manual. In my 1950 Commodore 8, I currently have AC 44's which are the comparable heat range of the J-7's. That car runs beautifully with those plugs. I imagine the AC 45's would do fine in the eights as well, for that plug is only slightly hotter. In my 1951 Commodore 8, I have AC 47's, and that car starts and runs fine as well. However, that heat range might be a little too hot for extended summer driving. It makes for easy starting, though. Back when I had cars with the 212 engine, I used Champion J-7's and J-8's, as I recall. The AC 44's and 45's correspond. Although I have not used them, Autolite should have plugs which correspond. Perhaps you can find an old cross reference chart for all these manufacturers.

Thanks to all for the info. Would a champion RH12 plug be to hot for the 254?