Seeing that the individual engine core pieces are over 50 years old when you find them, they tend to need a full recondition to be brought back to life. I see a cylinder head often for $1000 needing to be totally reworked and a block for $700 bucks. So by the time you buy all the core parts if your starting from scratch, the $5000-$6000 for a completely remachined and rebuilt 302 with new internal parts for that amount is really about right on target.