do-it-yourself exhaust system
 

Does it matter which kind of exhaust system is used? I can imagine that some extra hp's can be the result of a good exhaust system, but, if you have an exhaust without a muffler, can this damage your engine. I'm planning to make my own exhaust system with two cherry bomb mufflers. I will use the original exhaust manifold but I'll make the tubes myself. Can this be dangerous for the engine ('72 302 V8)?

Should not hurt anything but your ears.

With open tubes the engine gets damaged from cold inrush of air following wide open throttle then shutdown of engine. Cold inrushing air can warp valves. With mufflers, the inrushing air is heated sufficiently to prevent any chance of damage. With cherry bombs there is little chance of a problem if exhaust piping reaches the rear axle. Chances increase as the plumbing gets shorter and shorter. I would start to worry if the total plumbing length is less than 36".

Jeez ya learn something new everyday! Good point Jeff.