Hi, Eric, No offense taken . Your clutch is a puzzler, and I'll be delighted if I can ask the right question to help you sort it out. To isolate the problem a bit, (by the way, I like the suggestion to run the engine for a while to warm things up), will the car start while in first gear? It would lurch forward as soon as you start to crank, if the clutch is engaged, and sit still if the clutch is stuck in the released position. Knowing the answer to this will suggest where to think next, whether inside or outside the bell housing. (My cousin had a red 4 cylinder Fiero, 1984 I think, and it was pretty sharp. So the V6 must be a blast. Also, I worked on one (4 cyl) that had had an engine transplant that needed some tidying up, and wouldn't run right. Carbon plugging the MAP sensor vacuum source in the intake manifold was the culprit there. I looked like a genius to the customer, but I wasn't - someone told me to check there. My late uncle, a mechanic, told me that sometimes we look like idiots, and sometimes like geniuses, but most times the truth was somewhere in between!)
Did the clutch problem start right after the engine transplant? I'm wondering about the contact of the clutch lever with the release bearing, and remembering vaguely that that could be tricky. If it worked and you were able to drive the car after the transplant, it would be fine. Also wondering whether the release bearing is free to move on the transmission input shaft. I think the slave cylinder piston pushes a lever that clamps to (and turns ) a shaft that has (inside the bell housing) a fork that engages and operates the release bearing. Does that seem like your setup? Or does the slave cylinder piston push on a lever that pivots on a ball inside the bell housing and forks onto the release bearing?
Stephen