Yo Powerman, Couple things. This topic is beat to death, in the Big Block forums, spend a few hours searching. Secondly, I just did this exact project in my 67 Notch. It turned out great, and i don't regret it, but the costs are exorbitant:
Headers: $800
New Driveshaft: $300
Brake conversion (absolutely necessary): $400
Mounts, torque strap: $200
New Radiator: $1K
all new electronic: $600
Clutch, tranny,: $1.5K
On and on and on.
Like someone said earlier, before you pick up a wrench, know EXACTLY what you want, and be ready for it cost 6K-8K just to get the car on the road.
I already HAD the engine!