Been through everything, What am I missing?

[AASmedic]

OK Peeps. I need some input. I began having an issue back in February while driving at 65 mph on the interstate. The motor began to sputter and jerk and I thought it was vapor locking (as it was rather warm that week) or the fuel pump was going bad. I got off the freeway and drove surface street speeds (45 or less) and the issue seemed to resolve itself.

I finally got some time over the next few months so I replaced the fuel pump and all of the filters. Nothing changed. I then moved on to the carb and rebuilt it. I wrapped the fuel line with heat resistant tape and put a sleeve on it. Nothing changed.

I read another forum that addressed the same symptoms I am experiencing and it suggested that the pick up in the distributor was bad. I replaced the distributor, cap, rotor and coil, re-timed everything and nothing changed.
Another recommendation was to change out the thermostat. I put in a 160 degree thermostat and still, you guessed it, nothing changed.

What am I missing? Any help or suggestion would be appreciated.

Thanks,
Kevin