This is a long shot, especially because you've removed/installed the distributor... but If there's anything marginal with the ground between the distributor and the block, that can prevent the ignition from working properly. Make sure the distributor mount, the surface of the block, the bolt threads and their holes are clean and not slathered in oil.

I suppose it would make sense to confirm a good ground between the engine block and the chassis, too. And the battery - chassis connection. Again, this is a long shot. But what you're describing, with all of the troubleshooting you've done might call for a long shot.

Oh - though fuel issues might not be part of the picture right now, it's possible that the plugs are fouled from cranking the engine and trying to get it started. I'd replace the plugs (or at the very least, clean them really well). I've seen lots of Volvos that refused to start once the plugs had fouled, even after they were cleaned up and dried.

Good luck with this.

Cameron
Rose City