I'm going to buy a 300zx na, how much (ballbark) would it be to have the engine rebuilt, parts/labor, plus what kind of interior engine mods should i have done w/ the block ripped apart?

 

I have a 93 Z n/a 2+2 and I had the valves replaced (It happened because the timing belt tensor froze messing up the whole engine) and I paid for labor and parts $2,200 that's because I know the Mecanic. This is for you just to have an idea of how much it would be.