Thanks everyone for all the good info.
I've pulled the valve cover and the side plate looking for the cause of the thumping noise with no luck. It started suddenly and I really don’t want to just run it till it pukes. If it was a 2000 Yukon I wouldn’t worry about it. But with the miles I’ve put on it over the last 17 years plus however many it had before I got it, I figure it is about due. At my age with a good rebuild it should out last me.
Sounds like the new headers are out. I wasn’t really high on them and wanted the opinions of those that have had them.
It also appears that I will stay with the Carter carb. I have only had to rebuild it once and it has never given me any real problems.
I will be doing all the work myself except for the machining. This will be my first straight 6. That’s why I was looking for some input. I’ve done a couple V8’s and a whole lot of big diesels. (I’m a retired Chief Engineering Officer, U.S. Merchant Marine, so I mean BIG diesels, like a 3 foot bore with a 4 foot stroke.)
I admit that the new bed wood is pure vanity. It was just so pretty when I first put it in and the 4 coats of varnish were still fresh and new.
Thanks again for all the input.
