I had to do a tune up on my 1990 mistang gt. when i pulled out the old plugs they were all really old with corrosion. I gapped these autolite soark plugs at .54 ive bever been happier! My car is starting to come back to life. With of course new distributor cap and rotor and ford racing spark plug wires. I spoke with Tommy of LMR and he confirmed it will tie together nicely. Great bang for your buck. Shipping was fast free and easy! What more can you ask for!