I have a cam out of an lq9 6.0 which was in an 03 escalade was wondering if it will fit and any additional changes that will be needed

 

Yes it will fit. Depending on the year of your ls4 it may need a new cam sprocket. That lq9 will have a 3 bolt cam gear. 05-06 ls4s have 3 bolt and 07+ had the single bolt cam gear. You will also have to do the dod/afm delete. There are multiple companies that sell kits.