I am starting off building a 03 5.3 silverado. What are some of the cheapest mods with the biggest gains that i can do to start this build. So far i all i have is a flowmaster exhaust and k&n air filter. All replies are considered and appreciated. thanks guys!

 

tune is the most popular nelson/westers/pcmforless........do a search this gets asked like 20 times a day

 

there arent many mods that are cheap to gain any kind of good hp results.they all cost money.do a search on tunes. then get a nelson tune.

 

Cheapest mod and the biggest gain = Nitrous

 

speed gains found for good money are in converters i love mine that is what i suggest but power wise N2O is always your friend