Those injector bosses are machined into the flange adapter. It's all one piece.

This particular manifold came from a 1995 Mercury Tracer (USA). It was rated at 92hp 100tq.

The runners are 32mm ID 38mm OD mandrel bent tubing and are about 29 cm long after I cut them off and cleaned them up. The plenum is 54mm ID 60mm OD tubing with a stamped cap on one end. The stock throttle body is ~40mm.

It's a fantastic starting point especially since I only paid $24 at a local salvage yard.