Could you please comment this split I am currently doing.

Mon: Back, biceps biceps femoris, quads and forearms, heavy: 4-6 reps, 18 - 20 sets
Tue: Pecs, shoulders, triceps, calfs, heavy: 4-6 reps, 20 - 22 sets
Thur: Back, biceps biceps femoris, quads and forearms, light : 8-12 reps, 18 - 20 sets
Sat: Pecs, shoulders, triceps, calfs, light: 8-12 reps, 20-22 sets.

Goal is hypertrophy, currently taking 4500 cals a day, 6'6'', 220 lbs.

That seems a bit unbacanced. You are doing back and legs(the 2 largest muscle groups) on the same day. Whilst doind smaller groups on the other days.

I would advise either

Lower
Upper
Rest
Lower
Upper
Rest
Rest

or

chest shouldres back tris calves
arms legs
rest
chest shouldres back calves
arms legs
rest
rest

or

chest shoulders tris quads calves
back hams bis
rest
chest shoulders tris quads calves
back hams bis
rest
rest

i agree with meathead. you put all the biggeer muscles in one day, thats unballanced.

aside from that, if you want to get bigger arms you might consider doing tris on the day OTHER than the day you do chest and shoulders. and do bis on the day OTHER than your back day. however this will put you at a risk of overtraining your arms.

I really think an upper/lower of push/pull split is best.

Or:

Back/bis (or tris)
Legs/shoulders
Chest/tris (or bis)

Insert rest days as needed.