I just rebuilt my 8v and have all but the vacuum line on the side to the booster and one in the front to some emissions device hooked up.. Its cranking and is getting fuel and spark..
Your most likely culprit is a vacuum leak. None of the bosch engine management systems like um-metered air.
That "emissions devices".... is it a metal bottle on top of the valve cover, or a black UFO on the valve cover?
Seal of the open vacuum lines/ports and try starting it.
I'm currently out of my mind, but feel free to leave a message.
Check your camshaft timing!
When the same happened to me, it turned out that I attached the camshaft sprocket the other way around. There are timing signs on both sides of the sprocket. The motor had correct compression, fuel and spark, but would not run. As soon as I turned around the sprocket and set the timing, it fired up right away.
Good luck, Peter