I have a 1985 f350 with a 460 big block and want to put 4" stacks on it how hot will the pipes get i all so have a plastic bedliner

 

Well your not going to like my answer but here it goes anyway the only thing worse than stacks on a diesel is stacks in a gas truck. Stacks should have stayed on the large trucks they were meant for. Have a proper exhaust system bent for you at a local muffler shop you will be much happier and not lose any bed space or have a hole in the bed. Also your in the wrong place this is the super duty forum for 99- current model year the forum your model is located here 1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks - Ford Truck Enthusiasts Forums maybe a mod can move your post to the right place.