Thanks very much to all who responded during the engine rebuild tribulations that I have described hereon. I appreciate all the advice, it was all good and helpful. The story has a good ending.
I picked up the car this afternoon from the shop, and was told by the mechanic that the injector pump timing advance mechanism had been inadvertently mounted 40 degrees off, causing the injector not to advance on power demand. Today, it worked marvelously, much better power than from the old engine, good acceleration (though I expect better after break-in) and very, very smooth. This is the result that I was hoping for when I picked up the car after the engine rebuild some weeks ago.