if you can find a set of tri Y headders for your truck, you will love them. they are a 4-2-1 type headder, and keep the bottom end and midrange torque, great for the street. LMC has a set of true longtube headders to fit the '67-'72 GM 1/2 tons, 2 and 4whl drive. a copper headder gasket is a good gasket but, factory exhaust manifold gaskets work just as well for sealing. many use them with headders.