Recommended spark plugs for a 1978 F-25 W/ a single 318.

skuzzlebutt · Post by **skuzzlebutt** » Mon Apr 19, 2010 10:26 pm

Were up here in lake erie. Not sure if the fact that its very cool water will make a difference but thought i would mention it. Just curious what type of plugs we should run on this? We bought plugs last season and went off what plugs the recommended for that year in a chrysler auto and never put them in. Then compared them this season against the ones that are in there and they are different. (same brand though) So we just want to get an "offical" idea of what would work best. Also our channels are long from the marinas so we do a lot of low rpm running while in wake zones. (sorry use to two stroke PWC and fouling issues at low rpms)

ready123 · Post by **ready123** » Tue Apr 20, 2010 3:30 am

Champion XN9Y is what I use in my 318's... similar geographic location.

TC · Post by TC » Wed Apr 21, 2010 6:38 am

You don't want the wrong heat range in any engine. One heat range difference in a spark plug will not make a noticable change but you don't want to go too many numbers off. Installing an extended tip into some engines can cause interference with a piston.
If the recommendation for the plug came from a service shop and not the "guy across the channel" then I would go with that. I learned a long time ago, don't trust what is there cause anyone can put anything in.