I am in the process of fitting a new exhaust system. The old system was cobbled together by a muffler shop and the rear tail pipe hanger was a threaded rubber mount bolted to the towbar frame with a strap welded to the tailpipe. I want to revert to the original style rubber bushing mount as per the image. I also want to try and source the rubber bushings locally so I don't need to wait a week for an order to arrive from overseas. I am thinking that I could use readily available O-rings in place of the rubber bushings 665503. My guess would be nitrile O rings that are something like 50mm inside diameter and 64mm outside diameter might be appropriate. Does anyone have part number 667503 on the shelf that they could cast a ruler over and let me know approximate dimensions? I am planning to make the clamp myself as I have elected to run the 44.5mm tube all the way from the manifold to the rear rather than stepping it down behind the muffler. I'll make the clamp from stainless so that heat transfer is not as good so I think it should be OK with any sort of elastomer - nitrile, silicone, viton etc. If anyone is interested, I will gladly upload the dimensioned 3D dxf files I used to the the front and rear pipes CNC mandrel bent. It is for single carb/single down pipe model.