When I got back from holiday I naturally got the jeep fired up as soon as the freaking rain stopped. I got about 200 metres down the road when there was a fairly disconcerting growl from somewhere and the engine began to get very loud. Fearing the worst, I shot back to the garage, this was the issue:
The end plate of the silencer had disintegrated - not good news (but it sounded great!) I was happy it wasn't something worse.
Replacing it looked like something I could do, so off I went to Dallas Autos for a new one. Nice shiny new ones available complete with a comprehensive fitting kit.
Getting the old silencer off wasn't complicated but was a pain as all the bolts were tight with rust.
After a bit of cursing and a lot of WD40 I got all the fittings off. I replaced all the clamps, rubber insulators and the metal supports with the new parts from the fitting kit. Pretty straightforward job (even for me) which all in all took me about 2 hours. When I'd finished it looked like this:
Only one thing to watch out for on the test drive, the burning smell and grey smoke is not your head gasket blowing, it's just the paint burning off your new silencer.. phew! 
For All Your Jeep & Dodge Needs
http://www.dallasautoparts.com/
Thank you for publishing such an interesting blog.
It gives a real insight into the enjoyment, trials and tribulations of owning one of these classic vehicles... now I know what I'm in for when I own one!