Another thing I noticed while under the car was that both holding brackets for the exhaust as it passes through the cross member were touching the cross member. Leaving no stone unturned I cut a couple of bigger re-inforced rubbers for the brackets.
Well insulated now, but no joy here.
In the meantime my new spark plug shields arrived. I had to install the left and right rears from the bottom. I could just get the front shield bolts in by feel. So no more burnt plug wires now!
Also while all this testing is going on I came across a couple of TH200 4R transmissions in PEI. This one I dragged home is out of a 1984 Olds Delta 88 an comes with a later GM CG6F torque converter. It has a stall speed of 1,400 to 1,600 rpm, but it will rise with a higher HP engine. They were used in the 350 engines.
Next: back to the vibration testing.