Need Help on Choice with 2.7L Rebuild

[Bristol]

I picked up a '75 911S a couple months ago and am finally digging into the 2.7L engine. It looks like it will need some work - at least one head stud pulled, cylinders full of crap, and heads probably need valve guides/valve job. Bottom end looks decent, still I'm looking at some money and time to make it right.

Just as I'm getting into this deep another option comes along.... A buddy has a 2.7L that may be in better shape. It's missing some parts (fan, alternator, heater fan, front engine mount, etc.), but the engine I have is complete. I'm considering buying his engine as a donor spare or maybe just swap my parts onto it and get it running. I won't know the exact condition of his engine until I get the intake and exhaust off though and look at the valves.

What's a fair price to pay for a mostly complete engine like this in unknown condition? It's a 2.7L from a '77. Also, assuming I buy this spare, when all is said and done I'll probably have a spare long block left over with maybe some pulled head studs and broken exhaust studs, but otherwise decent. Is there a market for a long block like this (a core needing rebuild) and if so, what is a fair value?

Thanks in Advance!

Kirk
'03 996 C4S - Techart
'00 986 S - Gemballa
'75 911S - stock
'72 914 - Chalon