993 castings are 76cc heads. I wouldn`t buy it and why is because 993 heads are poor flowing with large inefficient chambers. Next the cam is the 327 350 horse factory blue print cam. This cam is based on 40 year old technology and there are far better cams out there. If this is a street bound engine the compression ratio is too high for pump gas. Plus if he didn`t set the quench distance to be tight this will only make it worse and the large chamber head has poor combustion characteristics which will cause it to detonate itself to death unless you slowed the spark timing down then the engine would be a turd.
You could find yourself a factory Vortec 350, which came with Vortec heads and a roller cam. You could do a basic hone and rering on it, get the heads clearanced for higher lift, throw in a comp hydraulic roller cam with .215 duration, a set of headers, a edelbrock performer intake and Quadrajet carb, HEI Ignition with a pertronix coil and module with spiral core plug wires. Don`t sound like much does it? Next take the 350 and the 383, install them both in identical cars with the same gears and transmission. That simple 350 would blow that 383`s doors off.