Just bought a 66 Skylark back in June of this year which was sitting in a barn for the last 24 years. It wasn't running and and the manual brakes (4 wheel drums) were all shot as well. I put in a new fuel cell (because the old tank was rotten), fuel lines, fuel pump, and rebuilt the Rochester 2GC w/electric choke. Installed all new ignition: points, condensor, rotor, dist cap, spark plug wires, plugs, coil, voltage regulator, including alternator & battery. Drained & changed the oil and she fired up right away. To my surprise she runs great and doesn't smoke (or knock). I've upgraded the brakes to a dual reservoir power master cylinder with rotors & calipers for the front end and rebuilt the rears with new drums, cylinders, shoes & hardware so she can stop now. Also just installed brand new Flowmaster dual exhaust. The bad news....after driving her (short drives) for the last week I changed the oil again and now I hear a "rod knock" sound coming from the motor (where it never made it before since starting her up). Needless to say I've already invested a good chunk of change to get it this far and was looking to have a "somewhat" reliable daily driver.... Anticipating worst case and because the 300 is a little rare and costly for a rebuild I'm thinking of swapping it out for something with better performance. Anyone gone through this or have any suggestions or insight on a cost effective performance engine/transmission swap option? Thanks in advance, any help is appreciated.