@Russell: Thanks, I'll look forward to hearing what you've got.

Eddy: What I'm trying to identify the differences in is in that thingamajigger that's in the second photo. The carb on the left (old) has it and the carb on the right (new) doesn't. I'm not sure what its called. If I could figure that out, I'd be able to re-plumb the new one around it, I think.

[EDIT] I found it. Its the Mixture Control Valve. Its listed on page 105 of the Raider FBC Driveability guide. I see no mention of it anywhere (need to look closer I guess) and I don't see any diagrams that DONT have it. I'm cOnFuSeD but in a good way. This is fun to figure out.

The truck failed smog with very high HC's at high RPM's, normal HC's at idle. Basically its running super super rich when the secondary opens up, from what I can tell.