troubleshooting a /6

Ok, one of the BABE teams is prepping a 69 Dart with a /6. Not my area of expertise but its pretty simple. It had been sitting for 15 years so it needed some love.

They went through it and got it running but when they hit the highway it fell flat on its face at 45mph. Runs great up to that point but then just dies out.

Initial investigation showed that the brand new rotor was suddenly mangled. All thoughts pointed to bad bearings in the distributor. So a new distributor was sourced and installed but still the same issue. Starts great, runs fine....right up to 45 mph. Fuel system has been flushed, new filter new pump....

Thoughts that I can pass along to these guys? I'm nowhere near the car so Im just guessing at things based on what they can tell me.

If the rotor in the newly sourced distributor got mangled as well, look to the distributor cap clamps or the distributor shaft shims at the bottom, it could be riding up due to the increase in RPMS.

If the new rotor on the sourced distributor is fine and the problem remains in spite of the replacement, check the vacuum advance on the distributor, replace the condenser, make sure that the points aren't closed, and fit a new coil just in case.

On these older, simpler engines, it's most often the small ignition parts that cause the gremlins to appear.

If none of these help, check the carb float and bowl and blow out the jets and circuits.

Hope it's something small.

Luck,

TC

Fuel delivery seems likely. Ignition problems would make it run poorly, misfire, lurch... No fuel flow due to a plugged up screen in the tank, say, would limit the amount of fuel and make it just kinda fade away. If it seems better for a moment after coasting down a hill with the throttle closed, then softens again once the fuel in the pump is used up...