I think it looks like a fairly effective design, covers all the main points of an effective block.
It could be optimised no doubt, but as a concept, i don't see any serious flaws.
I'd include a jet if I were you, and move the inlet pipe slightly further from the base. You may see a little backpressure from that block as it is.
Run some tests, if possible against another standard block, and let us know the results.
Keep up the effort
