If your in Europe and do not HAVE to buy from an engine builder in the USA check out Richmond engines
www.richmondengines.com (not much of a web site but he is a WICKED engine builder) he builds lots od Sprint car and boat racing stuff last time I was there their were 15 SBC stack injected engines in for a refresh. I have had 10-12 engines done by Jim that others had messed up and to date have NOT had any problems with them (not all mine mostly customers engines) Jim will talk your ear off, you will pat a bit more but that is because NO corners are cut. great guy, Honest will not screw anyone. super busy because it it.......... and knows how to ship worldwide.
good luck