You can do it, but it has to be perfect or the gearbox won't be in line with the crank and you'll chew out front seals in the box FAST. Not to mention input shaft bearings.

If you are going to do it, you need to make a template of the back of the turbo block, paying particular attention to the dowels, because they are what locate the box. Then transfer the template to the bellhousing and carefully drill the holes.

The dowels align the box, not the bolts. They just hold it all together.

If you do it right, it's as good as anything you buy that is turbo pattern.

Let us know how you go. Good luck.