changing long bed to short bed

I dont know if this is possible see i want to purchase a 2 dr rwd seirra so i can hot rod it... now its really tough to find a v8 with the short bed, can i change the long bed to a short bed if i goto a scrap yard and find a short bed?

I'm sure the frame would be too long.
I recall someone talking about this (maybe on the Chevy C/K list which is much busier). He said something about shortening the frame.
Bob B