Classic/Antique Car Repair: 235 chevrolet engine, vacuum advance, chevrolet engine

Question
Hello!  I have a 1958 chevrolet 235 engine, all original including carb, distributor, ignition, etc.  It is in my 37, and has worked flawlessly for over 13 years!  It drives well in town, as well as on the highay at 75.  However, recently it started to jerk and stall at high speeds on the highway.  It begins to jerk and shudder over 50mph, and then dies.  I have rebuilt the carb, changed the points and condersor, replaced the vacuum advance, and timed it.  ???  I have been done timing the same way for over 10 years by leaving the vacuum advance connected, and timing by using the first line clockwise from the flywheel ball indent.  Any ideas?

Thanks, Kevin

Answer
It sounds like it is running out of fuel. The cause could be a bad fuel pump, a fuel filter is so equipped, or a plugged fuel pick up in the tank restricting the flow of fuel. It is possable that it is ignition but I think that I would check fuel pressure ad volume first.
Brad