Build the 350. Parts are abundant. Hang onto the 327 as that is one hell of a motor. Run the numbers on the 396 to make sure it's a 396 then hang onto it. If it runs you can sell it for some good money or build it later. For a street machine either have the 350 bored and make a strong 355 or buy a stroker kit and make a 383 out of it. Either one wil be great for the street as you can only use so much of it anyhow.