With their air cooled motor; What was a good highway cruising speed? Could they cruise at 70 MPH and still run economically and efficiently?
Dunno about economically or efficiently, but not comfortably. It's not the air cooled part that's the problem. Displacement and not being designed to output a lot of power is. After a fresh rebuild that was mostly stock 1500cc(90 cubic inches or so), I pushed my '67 to a little under 100 and it did not like it at all . It handled 70 ok. The earlier 6volt models had smaller engines and weren't as fast. At 70 it started to feel light and having a crosswind hit you if you were doing above 80 would really get your attention. Long steep hills were also a killer for the poor little motors.
In 1985, with the hotrod motor, I got a ticket in Artesia MS on Hwy 45 for 97 mph. HP was being nice and told me he was writing it for that because if he wrote it above 100, he would have to take me to jail. Went to court in Columbus, it was taking forever and they broke for lunch before my case came up. I asked some official if there was any way I could get another court date because I had a test in a vector mechanics class in about 2 hours in Starkville, and they said the judge would have to ok it.... so .. I chased him down in the parking lot and caught up to him, as luck would have it, right next to my car. Quickly ran through the details to him, told him my speedometer was broken but now replaced, had a junkyard receipt for a speedo, the old speedo and a cordless drill in my hand and said something like "Besides, I don't think this thing was doing 97."(and kicked it's bumper) That got his attention and he said "In THIS car ?" I said "yes sir" while trying my best to will a halo into existence above my head. He said, "give me that" and snatched the ticket out of my hand and studied it over, looking back and forth between it and the car. Then he said "Go take your test and don't worry about this ticket, it's dismissed."
I never lied to him
