Shortening a long bed?????

[ToLowFoShow]

I have a 1972 Chevy truck long bed which im planning on cutting down and making it into a short bed. I have a few questions about this. One is does anybody know the measurements of the short bed truck frame and the long bed? How much do I need to cut out of the frame to shorten it? Im also planning on cutting the bed sides down to the short bed size….Does the front and back both need to be shortened or is the extra length just in the front. One last thing is the driveline. I know the long bed has a 2 piece driveline….what about the short bed? It has a manual trans in it. Any info would be great…thanks!