as you all know i have this 84 f150 that i swap in a 351w in with the GT40 heads from a 96-98 explorer. what spark plugs should i be running in this rig?? it's time for a tune up but i'm unsure on the plugs. i figure i'd better go ahead and do this while i'm doing this starter issue.

 

If you are using GT40 heads from a 96-98 Explorer, you need to get spark plugs specified for those heads, not for your model truck.

I would recommend MOTORCRAFT plugs. Original equipment for a 1996 Ford Explorer 5.0 with GT40 heads is Motorcraft SP-432.

What ignition system are you using? Those plugs call for a gap of 0.054, but a 1996 Ford Explorer used a totally different ignition system than what came on your truck. If you are using a Duraspark II ignition, I would go with a 0.044 gap.

 

Thanks for such a great response and with a part number! Im also gonna be replacing the ignition coil to so that gap might be okay but ill try it first!

 

Don't load down the old DSII ignition box with some super duper coil. People have not had good results from this, it heats up and shortens the life of the DSII box.

 

ok thanks for the heads up cause i was on the way to getting a 45000v coil to put on it. but you guy have the experenice with these olsd girls. i guess i'll leave her alone and just get the right plugs...