i have a 2004 5.3 from a 1500, my 2002 2500 hd 2wd has a 6.0, i am going to swap to the 5.3, will i need anything for the flywheel, or some type of spacer, the trans is a 4l80. and also i know the 5.3 has less torque and hp, but the truck has 4.10 gears and will the fuel mileage increase
I doubt fuel mileage will increase chief. Are you basing that just off of engine displacement? The 5.3 will have to spin higher to make the same power as that 6.0L, thus MORE fuel used because it will have to work harder to get the same job done. Id rebuild the 6.0L and be done. You'll have more "useable torque" where you need it for a truck with a larger displacement engine.