Posted on August 12, 2016 May 29, 2018 by FiTech EFI — 2 CommentsWhat size air cleaner should I use? Use the same size air cleaner you would normally use for your carburetor. Post navigationPrevious post: What kind of distributor do I need to control ignition timing?Next post: Can I mount the Command Center in the rear of my vehicle? 2 comments on “What size air cleaner should I use?” bill wilson January 25, 2017 i have a 1981 trans am with a 455 will the fitech system work with a rpm intake and a drop base air cleaner for the shaker . also what kit should i run not sure on horsepower around 400-450. will this work with ac. Bryce - FiTech Tech Pro January 25, 2017 All of our kits are broken down by Hp. We have FiTech At a Glance chart on the main page of the website that shows all of the features of each kit. All kits are the same dimensions and will fit with your intake. The air cleaner may need to be modified to clear fuel lines.