Save the 327 for something else or sell it to someone doing a restoration. 350 blocks are easy to come by, and 383 rotating assemblies can be had for a very good price. And with the additional cubic inches, you don't need a big cam to produce hp and torque. You will love driving your Chevelle with a 383 under the hood. The same goes for a 406, but good 400 blocks are getting hard to find.