I was thinking you could buy a ZZ4 long block? It'd be the same thing as you were looking at, just without all the accessories.
EDIT:
Yep. Jegs and Summit both have it.
http://www.jegs.com/i/Chevrolet+Performance/809/24502609/10002/-1
http://www.summitracing.com/parts/nal-24502609/overview/