at 6'4 185 i would opt to get on a program that focus' on the big lifts. I would stay away from most isolation work. I also don't see any problem with hitting a "muscle" twice a week, but i would not look at it as hitting muscles. Try and start getting stronger at the bench, incline, overhead press, squat, deadlift, bent row, barbell curl, dip, pullup, and so on. Try doing two upper and lower days a week. Put deads in the lower day, you could also do back in the lower day if you can handle it. Keep your volume moderate, i would not do 5x5 because it is going to be alot of volume for an exercise and you are not going to be focusing on one exercise a day. I would try somethig like this.
Day 1
incline 3x5-8
dips 3x10 hang weight if you need to
rear delts 3x12
barbell curls 3x10
skull crushers 3x10
abs
Day 2
squats 3x5-12
lunges 3x10-12
chins or pullups 6 sets of various grips
calves
Day 3
dumbell flat 3x10
Close grip bench 3x8-10
standing military 2x8
dumbell curls 3x10
tri pushdowns 2x15
abs
day 4
deads 3x5
hack squats 2x20
bent rows 3x8
GMs 2x10
calves
this is completely off the top of my head. But it address' everything. Their are things i do a little diffently but i am not trainig for aesthetics. Everyone is going to have their own opinion on what you should do, but I would staty away from the typical bodybuilder split, one day a week routine. The key to you getting bigger and stronger is adding weight to the bar every week and being conistent with your diet and training. If you are consistent and you do the basics and try and increase weight every week you will get bigger and stronger unless you are starving yourself.