[nikhsub1]

I have the "U" block, and have looked into converting it into the UH version. The problem I see, it the exit hole on the cover, it is VERY close the the edge and I fear drilling it out won't work, it is just too close to the edge.

<-----EDIT----->

After further examination, the intake and exit on the U top are stepped, that is they are wide at the top and take 2 steps down, to like a 3/8" opening into the block. If one could just thread the upper part of the holes in the top, a barb could certainly be screwed on to it. Ideally, I would leave the inlet hole stepped the way it is, this would create more velocity in theory, but the exit hole would probably benefit from being expanded, and this is the hole that remains the problem...