I agree. Sounds like you need another machine shop. The fact that #1 exhaust is not concentric tells me that either the valve head wasn't ground concentric or the guide is offset. If it was wear the sloppy guide would let the valve find home and still be concentric. I've seen guides so loose that you could move the valve and spring back an forth 1/4 inch or more, yet they still sealed compression, more or less.
It's unlikely but possible that the guide was machined off center but they would have discovered that when they ground the seat. Maybe that valve was chucked off center when it was ground and they didn't check the contact on assembly. Maybe they had a bucket of small-block Chev valves and picked one that was bent and didn't check anything. I'd say there is evidence of sloppy workmanship.
