What are the main changes I will have to make to my routine if I am going to make this change?
I am able to train 4 times a week fo around 1hr 15mins a time.
Currently I only train 3 times a week split
Mon: Chest
Wed: Legs
Fri: Back
I lift to max or almost max every session with low reps 2 - 3 leaving a full weeks recovery.
Always start with the main compund excercise for that bodypart and then move onto 3 or 4 smaller excercises per body area.
Hopefully this background will help you lot suggest some changes
Cheers,