I got a new timing set for the 400M I am putting in my truck.

How difficult is it to change the timing set on a Ford M motor? Are the gears pressed on? Am I likely to break something?

I got a set with multiple keyways. I was told if I change the timing I can recover some performance lost due to emissions controls. I am using an aftermarket 4 barrel and non emissions intake. If I change the timing on the gear set I need to degree the camshaft correct? What would be the ideal setting for the timing set for a non egr/emissions motor?

Thanks,
CHAZ