I purchased a kit online but have a question/observation. My factory stock '65 273 vehicles and my factory stock '72 318 vehicle did not have the special round washers on the two middle-inner bolts. The rounded washers were only installed on the two outer studs and on the two other bolts closer to the studs (total of four washers on each manifold). The on-line kit I purchased included washers for all bolt locations (total of 12-for both sides).

My understanding is the washers allow for expansion and contraction of the exhaust manifolds as they cycle through heating and cooling (running and non-running conditions). It seems the expansion between the inner two bolts was not deemed sufficient enough by the factory to warrant inclusion of the round washers at those locations (although I can't see how it could hurt anything to include the washers under all bolt locations). In other words, "factory correct" installation would mean four washers on each side and no washers on the inner two bolts locations, right? (But I am not saying that factory correct is important in this case).

Anyone have any other pertinent information to my comments/observations? Thank you.