[TerrysSPF]

Like others have mentioned, if you want to save some $$$ now then I would go with a 390 versus a small block. Then later on if you want to change to a 427 it will be much easier.

I think there are several other things you would need to change, besides the motor mounts and headers, if you went from a SB to an FE. Expansion tank, bellhousing, clutch, flywheel, throw out bearing, maybe the hydraulic clutch assembly, remote filter adapter, starter, etc........
I'm not sure about this, but you may even need a shorter drive shaft. (?)
There are a limited number of connection from the electrical system (guages, ignition, etc.) to the engine and they should be re-usable. But, IMO, it wouldn't be worth the hassle when you can build a nice 390 (and have the correct FE look) for the price of a SB.