I was able to take the diamond plate out of my 66. I assume my great grandfather had put it in there back in the late 60s early 70s because he used the truck as a work truck and didn't want the hassle of keeping up with the wooden bed. I hope he isn't rolling over in his grave after seeing me cut and chop this diamond plate out. Anyways, I used a 4 1/2" angle grinder with metal cutting discs. Took me the better part of a day to get it all down. I still have one piece to remove, but need to buy one more disc to finish the job. Here are some pics of what I did. I messed quite a few things up, but most of the things that are damaged needed to be replaced because of rust as you can see in some of the pics. I think the lower braces are going to be able to be saved. I will need new wood and new strips. Hope I didn't mess up more than what I should have by removing this. Thanks for all the advice so far. Here are the pics. http://s1050.photobucket.com/albums/s407/Boomerchevy66/Bed%20remodel/

1966 Chevy C10 Longbed
"Dave's '66 Custom"
In the Stovebolt Gallery
More pictures on Photobucket

Anything that's hard, will always be worth it in the end.