Selecting a supplier for a long block depends on where you live, since it's a truck shipment (kinda heavy!)
I live in PA so I bought mine from a company in 'Jersey (and am pleased with it). Under 2 grand, delivered.
A "long block" consists of a rebuilt engine with heads. (A "short block" lacks the heads.) You need to get heads as well, for they may be cracked as well. You transfer over your intake manifold, timing cover and pulley, distributor, oil pan, etc.
Jeff
"...reality is not nearly as lovely as the world of Liberal Land. No wonder so many people want to go there." - Tom Sowell