The problems in threads under the other headings have been fixed (updates coming)
Today was the last test drive before arranging delivery.
A run at highway speeds.
Took it on a stretch of expressway that had some hills (most are flat).
It easily got to 65 at about 2600rpms and cruised nicely, but lost speed on the hills. Cycled the A/C on and off and the OD in and out. Made little difference. RPM increased to about 3200 on the hill but speed didn't increase.
Anyway on the last hill everything went to hell.
Noise ,lost power, vibration. It was firing back through the rear carb. Ducked over to the breakdown lane and it was pretty smooth at idle (with an obvious miss). Oil pressure good, temp good, no smoke, no fluids leaking.
Limped it home to find the following
Plugs looked good. Comp test 120,120,120,0,0,120. top end of valves looked good.
Will take the head off tomorrow.