They don't need to be banned to come off the road. They will be gone through attrition. I have a 78Z car. 35 years ago, they were plentiful. 20 years ago they were still available in the yards. 10 years ago the message boards were thriving. I haven't seen one on the road as a daily driver in years although I'm working on getting mine back.

The same with 1st & 2nd gen Dodge Cummins. 1st gen is almost gone. We know everything needed about the 2nd gen and parts are plentiful. The message boards are shrinking and the trucks will be mostly off road in another 10 years.

At least the engines with the mechanical Injection pump "can" be made to run even if commercial fuel becomes unavailable. There are lots of big trucks running diesel so I doubt that will happen soon. Technology isn't there yet.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.