Im playing the plug and wire game with my 97 4.6. tried autolights that worked for awile but startewd misfire on #1 cyl.Then read on this forum about nothing working but motorcraft so had mtrcraft plugs put in but not wires.Now misfiring again going to put mtrcraft wires on my question is is there a differance between the 5 and the 9 mm wires.The price differance is only 25 bucks so thats not an issue IS BIGGER BETTER. thanks.

 

Larger the better. The core might be the same size, but the more insulation on the outside, the longer life you will get out of the wires before they break down.

 

Go for the 8mm. Or 9 whater they are and the motorcraft branded ones are very good.

 

stock motorcraft ignition wires are 8mm wires... FMS makes 9mm MSD makes some 8.5's and nology has some price rape ones for 276 that are 9mm id go for the FMS ones they are around 70 bucks for a set the cheapest of all of em and the largest wire

 

MSD Super Conductor wires have nearly the lowest resistance of any out there at 50 ohms per foot. I've put them on a few of my Jeeps and each time noticed a smoother idle and better throttle response. I should say that each time I've put them on I have also opened the spark gap up by .010"-.020" depending on the vehicle. The plugs did not appear to have a shorter life due to the plug gap increase and the coil was never a problem either. I think I paid around $56.00 for the custom fit 6 cyl sets from Summit. I have never had a plug wire come apart on the MSD's either. I have had Jacobs wires come apart and crack within 6 months. I don't know if MSD makes a wire set for the 4.6 but a universal set comes without the plug ends unattached. The kit will give you a tool to install them and it works great and is easy to use. The ends have never come apart on me. Good luck with whatever you go with.

 

My understanding is the Motorcraft and Autolite Spark Plugs are the same.
I run Autolite DP's and 8mm Motorcraft wires. The combo really smoothed my idle, and my miss is gone. Did fuel filter, and PCV valve at the same time.

Wires were $75.
Plugs were $30.

 

msd wants 81 for a set of their wires for our F150's