This is a continuation of the last post, but really deserves its’ own space.
I spent most of Saturday down at The Shop working on the truck - I did new belts, wires, plugs, rotor and distributor cap. It was all quite due for some updates, as the fan belt was actually missing teeth and the distrib. cap was quite grooved on the electrodes. I had been experiencing a bit of an issue trying to get the motor all tuned up — I know there is more power and gas mileage to be had.
The replacement parts went on like a champ and did a good job of smoothing out some rough spots, and overall the truck performs a bit better. Since there were so many knowledgeable folks there, we started looking into tuning it up further — just for fun. What we discovered is a bit odd — the firing order on the distributor (Chevy HEI) is correct, but it is indexed two plugs counter-clockwise from “normal”. This is not an issue in itself, but is something odd that needs to be corrected before moving on. The real issue turns out to be that the motor was not vacuum advancing. From what I’ve read, this type of advance is only going to give me increated economy, but it something that just should work. Landon eventually discovered that my vacuum line from the carbeurator to the advance canister on the distributor was plugged, so we removed the BB and reconnected things. Now, when the advance vacuum line is connected and the motor is held constant at anything other than an idle, it runs like crap, wanting to die, etc. We tried tons of stuff, but in the end we plugged off the vacuum port on the carb and just left it as it was before we removed the blockage — it at least runs fine then.
I will start going through things to narrow it down, the first being the odd timing of the distrib — need to find TDC again and properly time the thing. Next up will be a rebuilt carb. If that (and several hours of tinkering and drinking) do not solve things, I think a trip to the local mechanic is in order. Feh.