Dreamin,
You best try some Google searches, or look on the EAA website for discussions about the present FAA position on this. The FAA started to more tightly enforce the regulations on experimental amateur built aircraft a couple years ago. They made it clear that if you take components of a previously certificated aircraft, and incorporate them into an experimental, you can't count the work in them, including your efforts to restore, say, a wing or fuselage, towards the required 51%. They say that you are simply doing repairs of an existing part, not building anything towards your experimental amateur built aircraft.
I know that there have been many experimental aircraft built up from major components of standard certificated aircraft in the past, but the FAA basically says no more. Others will probably add to this thread and disagree, or have other interpretations, but my advice is to check out the written words from the FAA and the EAA, and not just go on posts like mine! Too much money and time is involved to not do it legally.
Good luck with your project. They can be built, as posted above.
Chuck Shaw