^^ A new one (FTR) or an older chassis?
As I am sure you are aware, the FTS was never sold in the States, not sure about Canadia.. Are you going to convert it to 4WD?
There is an Eaton axle similar to the OEM version for that truck, with a selectable locker. Some M/T tires and a locker will get you a long way in a big truck. The Isuzu (Duramax) inline 7.8 liter six cylinder is a pretty good motor and can be turned up to 300 HP and 860 TQ pretty easily if you want more power. Some versions were only about 200 BHP, so the trucks are really turds.
A 335 MPT will fit easily and a 365 will fit with some trimming or a small lift. Factory wheel cut (2WD) is at least 50 degrees, so they turn really well. Avoid the CAT motor that came in some of the early trucks, they are garbage. Interested to see a build thread when you get started.
Cheers
PS: Glad to delete this if it is too far off topic.