Mission accomplished. My thanks to Andy, Bill, John, D.J. and J.T. for your ideas and cautions. I replaced the mixing elbow recently and your advise really helped the project. Once I had the inboard bolts removed from the manifold, about the only way to wiggle the collar and elbow out was to leverage it with the exhaust hose agains the muffler. Once that outboard joint was pried free, I was able to twist the whole thing out and take it home to really tear down. While I was at it, I also replaced the exhaust hose to the muffler; pretty much had to since I couldn't get it off the end of the elbow. I swear the engine starts easier and runs smoother since the new hardware has been installed. Thanks again for your guidance. TAH