1971 Cougar XR7 - Stops without warning

On behalf of my Dad, who has always worked on this car from day one and kept the beautiful car running like new until recently…

It has a 351 Cleveland motor - 4 barrel

It starts up and runs down the road only to

stop without warning. The motor turns over again and starts up but it repeats the stopping and starting. He has done the usual: replaced the fuel filter, adjusted the automatic choke - in the garage he has it running at 1000 RPM’s and ideals it down to 650 RPM’s and it dies

Any ideas? Thank you

Does it run fine for a while after sitting? I’m going out on a limb here, but is it possible the fuel cap vent has become clogged over time and is causing the pump to work too hard to draw fuel from the tank? It’d be simple to check; just take the cap off and go for a ride to see what happens. Beyond that, maybe the fuel lines before the filter have become clogged. 40 years worth of gas flowing through could certainly clog 'em up.

I would look at the ignition system.