1950 GMC 300 truck

Ok, so my cousin and I are going to start work on either restoring or modifying a 1950 gmc 300 truck. The thing is that we aren’t sure how much it will cost to restore it, because we can’t find parts; so we can’t price it. Another idea is to modify it by pulling the i6 engine that’s in it and dropping in a 350 Chevy turn-key engine with 320hp and putting a new transmission in as well for around $12,500 just for the trani and engine, or we could keep the original 97hp i6 engine; which is running by the way, but we don’t want to go down the wrong road and end up spending $600,000 on a vehicle that still doesn’t run. So if we restore the truck to at least drivable condition we need a flywheel, a clutch plate, a 6v fuel pump or fuel pump settling bowl, a 6v battery, and some detergent-free engine oil. If we go down the modification road we will need at least a new engine, a new transmission, a new differential, a new driveshaft, a set of new 20″ 8 lug dualy rims for the rear and just new 20″ 8 lug rims for the front, 6 new 20″ truck tires, an exhaust system or tubing to build our own, a 12v fuel pump, a 12v battery, and all the extra little wiring pieces that are needed that aren’t already on the vehicle. So as you can see we know that the original parts will be expensive but we will need less of them or we can modify it for maybe the same price but more stuff will be needed; again we’re not sure of the original parts prices because we can’t find the original or even aftermarket OE spec parts. If anyone knows where to find these parts, has these parts and is willing to sell them for fairly cheap or has any other ideas of what we could do with this truck, please say so.