I have an 05 silverado that I was looking into putting a cam into it if I do would I have to change the tune
Dylweed94 welcome: Anytime you replace a factory cam with an aftermarket cam you automatically are going to change the tune of the engine. Aftermarket cams are made to give you more performance, and to make you feel that performance, when you step on the gas pedal. Remember any time you replace a cam, you should replace the lifters. Also replace the timing chain. Even if your engine has 10,000 miles on it,it has enough stretch in it to retard your cam 4* or more. MAKE SURE YOU FOLLOW THE CAM MANUFACTURERS CAM BREAK-IN PROCEDURE...Thats another reason replacing the lifters is an important part in the cam break-in. Lifters have to spin in order for them to 1.Mate and create a nice wear pattern, 2.On SBC the lifters pump oil thru the push rods to lube the the valve train and its componets. 3.Hope that answered your question.BobAs far as an engine tune up not really. I would replace the spark plugs, fuel, and air filters, and the oil and filter.