327 engines are getting rarer and rarer as time goes on .. the last one i found had been sitting open to the ellements for 5 years and was solid rust on the inside .... all for a mere $500 ... i left it .. lol
body panels are easily bought aftermarket, and there are a number of suppliers for all the little bits and pieces to the point that just about ANYTHING can be gotten new for that body style truck
bucket seats are best aquired from a salvage yard, as is a tilt wheel - factory tilt wheels werent very common for these trucks, and for my i actualy picked up an 80's camaro tilt column that i was going to make fit
There is a guy up here called "Scotts Super Trucks" that specializes in the '67-'72 Chevies. I've dealt with him numerous times on a few different trucks, and he's always been great. Now sure if he has a website or not, but I can get you contact info if you want it.