Sorry guys I did't see all these replies. I actually was talking about making a 72'-75' D100 long bed single cab into a short bed single cab. It sounds like the rear section of bed behind the rear wheels is the same be it long bed or short bed. Sounds like you just need to take 16" out of the front section of bed in front of the wheel wells. Can anyone confirm the rear measurement of a long bed and short bed from the rear of the wheel well opening to the rear of the bed?