sounds possible. if a masada has a version 2 and the dimensions are close enough. i just stuck a g&g gr16 gearbox into a scar. kinda had to jam it in there. I even had to use a cutting wheel to cut a bit off the gearbox, drill it out a bit, and modify the selector plate from the scar to fit the gearbox. I was freakn scared to test it today, other than the selector bein a bit funky it works Great. :D
Not drop in. Air nozzle is longer on the A&K Masada, plus the KWA air nozzle will work only with KWA hop up unit.