I am thinking of removing my middle silencer on my '72 3500S, what size of pipe would I need to fit over the existing pipe. I plan to cut fairly close to the silencer to give a fairly straight run of pipe as it is a bit kinky under there! I would make up a bracket to attach to the existing silencer hanger. I realise that once I have done this, I will need to get new needles. I am not sure which ones are currently fitted, but will investigate & seek advice on here as to which would suit best.