When is a part no longer worth restoring?

[Dexterpix]

Hi All,

I have the original to my 1966 911 (built Oct/Nov 65) 2.0lt sand cast engine, in pieces. The PO had modified this into a 2.5 using Mahle 90mm RS P&C's. I am reassembling the engine using 2.7 heads and new 90mm P&C's

My question: I have the original date code 6 thru 8 65 heads opened up to accept the 90mm. Is this mod reversible at a cost that makes sense? Is there value to keeping these with the original case? I have no plans to sell this vehicle, but plans change. I made mistakes previously by selling other original parts 15yrs ago when I bought this vehicle. (the original solex's with air filter setup) Have these changes to the case and heads made them irrelevant to the value at this point.

When do the original parts for these early 911's become no longer restorable?

Thanks
Joe D

[NorthernThrux]

Keep them. They can be sleeved easily enough I suspect. Don't throw original stuff out that can't be replaced unless you are absolutely in dire need of space. Having the original heads will add some value to any future sale. How much is debatable, but it's better than throwing them out.