Here is something you may not be familiar with its called hard work and dedication. Over time that equals great results. Your looking for the easy way out, and there isn't one. If you can't surpass 140 on your own then your training and diet suck. Your own delusion is making you think that you have exhausted all of your natural ability to make gains. I bet if you laid out your training and diet we could find a bunch of holes.
This is basically what I have been doing for the past 3 weeks
My current workout routine is this
Day 1: Legs (Back squats, leg extensions, dumb bell lunges, straight leg dead lifts, hamstring curls, and calf raises)
Day 2: Biceps and shoulders (Seated military press, Barbell/dumb bell shrugs, Arnold Press, Dumb bell lateral raises, seated bicep curls, hammer curls, preacher curls, chin ups, reverse bicep curls)
Day 3: Abs, obliques and cardio (decline crunches, planks, leg raises, mountain climbers, Side Jack knives, Seated trunk rotations, Side bends, Sprints, elliptical, and sometimes jump rope)
Day 4: Back (Dead lifts, hyper extensions, lower back machine? [no idea what it's called], pull ups, barbell/cable rows, and Straight arm/lat pulldowns)
Day 5: Triceps and Chest (Bench press, Incline bench press, decline bench press, dumb bell bench press, dumb bell fly, push ups, dips, lying tricep extensions, tricep kickbacks, Skull crushers, and Rope tricep push down)
Day 6: Abs, obliques and cardio (decline crunches, planks, leg raises, mountain climbers, Side Jack knives, Seated trunk rotations, Side bends, Sprints, elliptical, and sometimes jump rope; as of late I like walking for an hour as I heard it can help burn fat without burning muscle)
I am currently using the ECA stack as well.
I am on a ketogenic diet, eating about 400 cals x 5 meals