I have developed an exhaust leak in the area of the #1 or #2 cylinder. The engine is a 1981 L28. This motor powers my 260 and has the stock exhaust manifold. I suspect my manifold gasket is leaking. My question to you is, does anyone have a recommendation as to a particular brand of replacement gasket. Are they all about the same or are some better than others? Thanking you for your inputs!