Does my /6 sound right?

What do the spark plugs look like? Pull a few of them and see if the firing tips are black and sooty indicating a rich mixture or tan/grey as they should be. For reference, Tune-up parts and technique suggestions in this thread and Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.

Check for a slack timing chain: Pop off the distributor cap and, using the belt and fan blade, manually rotate the engine in one direction until you see the distributor rotor begin to turn, then see how far you can manually rotate it the other direction before the distributor rotor starts turning. Use the timing marks as a guide/gauge to how many degrees the crank turns before the distributor moves. If there is more than a degree or two of perceptible lag, the T-chain is slack and/or the cam sprocket is worn.

Other things to check: make sure the mechanical and vacuum advance mechanisms on the distributor are working, make sure the manifold heat control valve is not stuck, and make sure there's no excessive exhaust restriction.

Once all that's checked, you will need to move on to things like compression or leakdown tests. How many miles are on this engine?