E3.74 E3 Premium Automotive Spark Plugs (8-PACK)

Haven't installed yet on the 6.4 but have them in my Ram 5.7 for 7 years and no problem.

Truck is running smoother

Do not use in a new Sierra2022.Start stop will stop working

Changed them out then made a road trip of over 500 miles. At first not much improvement, mileage was a bit less than before. I was at first disappointed but he more I drove the better my mileage became. Getting about 2.5 per gallon more now at 60 mph

Fit like it was suppose to. Shipping came from two locations but did arrive on time.

Fuel improvement and better response