The intake manifold gasket position can easily be overlooked on the 8v head. The #1 port (A) gasket does not sit in the same position as the other three ports (B). It's flipped from the others. If this gasket is installed incorrectly, you can impede the fuel injector from spraying fuel into the cylinder head properly.
The cut-out in the gasket needs to align with the cut-out in the head for the fuel injector spray.
If you think you may have this problem, or you want to rule it out, you can view this by removing the fuel rail and injectors and look down the hole where the injector was. It will be obvious if it's blocked