I didn't mean to take this long between updates, but what I expected to be a quick vacuum-advance unit replacement turned into one problem after another.
I found a NOS advance unit and got some solid motivation at the start, but after pulling the plugs, wires, and distributor and slapping the advance unit onto the dizzy I realized I had no idea what I was doing. I was following a couple of tech guides on Deve's Technical Network, but I'd never done timing before and hit a bit of a mental block. After a couple of days I thought I had it all figured it out, but I couldn't figure out for the life of me how to static time it as I couldn't get electrical power through the coil which was baffling me.
A few days and a bit of electrical troubleshooting later I figured out that the starter switch was shorting electrical power directly through the frame of the starter and to ground. Either I tightened the nut down too tight or the integral washer was too loose, because when I tightened it down the lug turned, and this shifted the internal parts until they broke through the cardboard insulator and made a connection from the positive lug directly to the switch body.
I put a new starter switch on it and struggled for another day to figure out static timing, but eventually got it set up pretty well. Then came the moment of truth...or so I thought. I pumped the gas pedal, applied just a bit of choke, and pushed in the starter pedal and...nothing. The starter wouldn't work.
After a bunch more troubleshooting on the starter, disassembling, cleaning, and reassembling it multiple times, re-seating the brushes, and re-cleaning it, I finally got it to work. I think there was just a continuity issue between the starter switch and the positive post on the starter itself. I'm not fully sure though, so I still have the starter removal tools sitting on the dashboard.
I finally got it started and it ran like dog crap for a few minutes, I think due to bad gas, but it smoothed out after a few minutes. It was time for the big test, so I loaded all of my tools in the truck, took it around the block a few times to gain confidence, and then hit the long, straight farm road nearby. And I got up to a whopping 44mph. So in total I've made an improvement of 1mph and that improvement may or may not have been a fluke. Bah humbug!
Am I just expecting too much from this truck? The rear end has the factory 4.57:1 gear set and it's only on 28" of rubber, but I thought I could at least push it to 50mph. On paper the truck should hit 50mph at ~2750 RPM and 55 at ~3,000 RPM. Are these 235s really that low-revving of engines, or is there likely still some problem I have yet to discover?
I did have a small victory in figuring out that the idle speed screw likes to back off, which is why the truck died on me last time I went to the gas station. The screw is torque-striped now, and that alone seems to be holding the screw in position.
