Early 911 - Engine Rebuild Costs

[mph]

I've heard some astronomical prices bantered around for rebuilding these engines (1960's models).

Are they expensive to rebuild and if so, why ? Who can do it and what is a typical cost ?

Another reason I ask is that I know the whereabouts of a 911E that may be for sale. It needs restoring.

[mph]

Well there's a 2.2T currently advertised with an engine rebuild cost of £24k by Tech 9.

I would consider that expensive.