Just got to thinking maybe I was an idiot and swapped the hoses around, but I don't believe so. I will definitely check for that, but I followed the diagram on the hood just like the last time I had it apart and it ran fine then. It idles smooth as glass with the purge line disconnected and the carb port plugged, but if I hook it up it gets rough at idle and has a stumble. With that carb port open it dies almost immediately. The other line off the purge valve is hooked to the hard line the is sort of Y shaped just rearward of the carb. That hard line hooks to the distributor advance at the other end. Could be I have the source vac hooked up wrong on that hard line. Disti isn't advancing at idle though, I did check that when I got it timed. I had the purge line hooked to a small vac port toward the top rear on the side of the carb, the only thing that matched the diagram really. But even if I got that one wrong, the other should keep the valve closed at idle so it would not affect anything.
That line on #1 intake runner goes to the vac switching valve on the smog pump I believe. In my case, I don't have a smog pump any more because the impulse head had no ports for the AIR manifold. In short, it is already plugged.
The motor runs fairly strong, but it does seem rather weak in the low end. I have a slight stumble coming off idle, but not bad at all. A big plus is that the constant pop out the exhaust between shifts is completely gone.
The motor that came out of this truck lost compression in #1 cylinder after a mildly high speed run over 8-10 miles. The spark plug looked like the metal of the ground electrode had been melted. Not sure if that has any bearing on the problems I'm facing now, but I though I'd mention it. I was thinking detonation, and your comment about that #1 runner vac port got me thinking perhaps I had a leak there leaning out just that cylinder, which could have caused my problem.
Well thanks for your input Jerry. I need to get some time and really go over the vac routing again to make sure I'm not off somewhere, and maybe just try the spare canister I've got to see if that helps. Hopefully I'll have a nice day soon to get back to it, rained hard yesterday and snowed hard today. Sucks when you don't have a building to work on your rig in.
