To answer the original question - Yes.
I think the first area for performance would be the exhaust, especially the drivers side manifold, and going from the stock single to dual.
As for value I think $8,000 would buy a rather nice early Barracuda.
I think the above reply of $15000 or so is probably pretty close, around here in SoCalif under $10000 don't usually have an engine at all and are basically rusty junk. Prices here are crazy. However I think I'm going to pass on this car, my car (streetrod) is upwards of $28000 to $30000 although I'm asking $25 cash, I don't mind taking a slight bath but this one may be too far off.