Technical Engine bogs with throttle

I spent some time today working on a stock '56 292 y block. Valves were adjusted, and threw in new spark plugs, points, and condensor. The engine now idles pretty well in neutral, even revs up in neutral. Problem is, when I put the car in drive or reverse, the engine seems to begin to shutter. When I apply throttle, the engine bogs down and eventually dies. I then have difficulty getting the car to restart.

Does this sound like a timing or carb issue?

 

What distributor are you using? Get rid of the load-o-matic (full vacuum) and use one later than 57.
Power valve may be leaking or blown.