This is VERY unlikely, but I long-distance trouble shot a similar symptom 6 or 7 years ago that drove me nuts (usually a short trip). I had an old dwell/volt/ohm meter that I was no longer using that I shipped to Kansas City for the guy to use and we had 3 or 4 phone sessions to figure out the problem.
His truck worked well at low engine speeds, but by about 900 RPM the points started floating a little (and dwell was going down. By 1500 RPM the dwell dropped to near zero (points open all the time) and the engine refused to go faster.
Turns out the brand new set of points was missing the stainless steel spring and was depending on just the brass spring to close the points. The brass spring (really there to conduct electricity, not be a real spring) didn't have enough tension to keep the points from floating. The owner had never closely examined a set of points, so he didn't know anything was wrong. Replacing that set of points with another new set solved the problem.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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