hi volks

have a question 

found a motor head to head with alt. for 100.00 smackers. person said it ran
great before the van was totalled (front end). its been sitting on the
concrete floor for 2 years. it wont spin by hand we will be taking tools the
next time we stop over to the guys house. is there anything special i should
look for as far as problems? i mainly deal with air cooled motors for my
type 1-2-3 but this monster is a bit different. and if the heads are good
i.e. crackless than i was planning on replaceing intake and exhaust valves
and guides install new head gaskets and such and be on my way.

reason i ask is my 86 vanagon (i.e.terrorist bus) with a mere 160k miles
seems to have a problem with compression. say 120,121,147,168psi per cyl. i
say she is just getting broken in. good thing is she burns no oil. heads do
not leak external but believe theyre leaking internal. i loose power after
warm up.
is there anything that i should know before starting this fun project?

any input would be greatly appreciated
thanks Jonce 
56 single cab
66 square back
66 bug 
86 vanagon
92 jetta
94 probe (wifes car)