Hy Guys, I'm not an engineer, I'm a mechanic, and most of my learning comes from "experience" (experience is what older guys call their mistakes), early in my career and friend asked if I could help him with an exhaust leak on a Chev small block V8. I took his exhaust system off the engine (ram Horn manifolds), and I took them into work the next day, to the machine shop to check them for face flatness, they were in perfect shape. The company where I worked had just started stocking "Lamaloy" bolts so I bought the correct length bolts to install the manifolds, that night after supper I installed the manifolds and torqued them to spec. everything cold, I phoned my friend and told him his car was ready, he came over and picked it up. The next night after supper my friend called to say the car was noisier than ever, I asked him to bring it over if he could, he did, and when we checked it, ther were no heads left on the bolts, the manifolds were hanging on their now grade 8 studs. I did learn in other circumstances where grade 8 bolts were not appropriate, but this was my first experience, and I have never forgotten it. I redid the exhaust manifold job the next weekend using grade five hardware, and he had no more noise or problems while he owned the vehicle, at least three years.
