When you see these small holes don't panic.
They are on purpose. AFTER the block is bonded or
tig welded to the runner tubes you take a 3/8th drill and drill
in from the injectors opening through the .065 thick
wall of the runner. This is just a starter hole for
your drill. If you mount the block on the bottom
leg of the runner you will need a long 3/8th aircraft drill
indeed. My guess is something like a foot long.

BTW put the blocks on top of the runners whenever possible.
That way if the injector O-ring seal leaks the fuel will flow into
the runners and on into the engine and not back out and along side
of the injectors and possibly down on the exhaust manifold.

As in these two drawings.

Paul Lamar

Thanks for sending the stuff.  Great packing job!  All the parts are made
very well.
Ernesto