After a few more months of chasing Gremlins, the car, as Barb put it, is like a real car. List of boo boos and remakes is long:
The transmission started to make noises.
The noise from the engine quieted but never went away.
The new oil pan was resting on the cross member cut out.
Oil pressure would drop to zero on hard left turns.
The only solution was to pull the engine and that is a BIG job. Well, maybe not the only way. I pulled the cross member, then the tranny. Replaced the tranny with a fresh (25,000 mile) junk yard unit. Pulled the oil pan and relocated the oil pickup and made it about an eighth of an inch longer. The rod ends had bashed the windage tray pretty good, leaving bits of steel in the pan. So I removed the tray, cleaned up the pan and reinstalled it. Then cut some more clearance in the cross member for the oil pan and reinstalled everything. Took something like 8 days. A miracle around here.
The changes all worked. The "new" tranny is great. Shifts great, so I suppose those fancy synchronizers pay off. The engine is now very smooth. I had doubled the engine mounting biscuits, it now runs on 1 1/2" of rubber on each side. The vibes around 2,000 rpm are gone. As a plus, the engine no longer sounds like a thrashing machine.
But it still did not run right. The tune was very unstable, especially at lower rpms. After a few weeks of changing things and no progress, I checked the back pressure on the fuel return line. Ten psi with the engine idling! I called RootsRacer (the supplier of my ECM). He said the back pressure should essentially be unmeasurable and recommended a minimum of 1/4" I.D. return line and preferred 5/16". Well that was the issue. I had posed this question years earlier and the answer was 1/4" minimum. He meant I.D., I thought O.D. as I was using tubing. So I ended up with 3/16" I.D. (When I nod my head, hit it.)
Anyway, a trip under the car and I could see no way I was going to snake a 3/8" tube the length of the car. Maybe if there was no wire going through the frame openings. The only way I could see to do 3/8" was to remove the wiring, install the tubing, reinstall the wiring. Not with the temps in the mid 90's. So I used 5/16" brake tubing, which about doubles the flow of 1/4" tube. Big enough job! Especially around the steering arm.
The return line pressure is now in the 1-2 psi range, I think. I am using an ordinary pressure gauge and it is impossible to get a reading. The needle moves off of zero, but not into the area that is calibrated. The car is now much more predictable, especially at idle and low speed throttle response.
We have been working on tuning the engine for daily driving. It is getting close. The tuning map is a nightmare. There is a column of mostly .93 next to a column of .98's. I'm fairly sure this is due to the long, small I.D. runners on the intake manifold. It would be interesting to see how a similar manifold with larger runners would tune and perform. Maybe someday. But maybe not. All that low end grunt is nice. After a drive, my oldest son referred to the car as "The Hill Climber". It is an apt description.
WOT tuning has a way to go. It is still a little lean at WOT to make max HP. But there is enough power that you'd better have the car headed in the right direction when punching it in low gear.
Right now, I think the car is ready for some long trips. We are planning a trip to Columbia, MO (about 450 miles) in a couple of weeks. Then the Invasion and finally, a trip to Northeastern Ohio in October.
Bill