Hmmm. Now I have some decisions to make.begween the 44 or 55 AF1 for an 8.38
Easiest way to go is this (even though it is not the be all and end all of truck to deck size ratio):
Wider truck for more stability, usually better for transition and anything that you want the wheel to sit at the edge of the board, without it sticking out at all and the board being well balanced.
Narrow truck for street skating, rail and ledge balance, board tech, flip tricks and the like, where the wheels sit under the board, so you don't see them at all and the board being a little more tippy on the side.
There are pros and cons to both setups, but when dealing with truck sizes, that is often the easiest way to look at it. I have the AF1 55 size on my 8.38 boards wanting more balance, but another guy I know has the AF1 44 size who skates rails, ledges, lots of flip tricks and says they skate better for him than the 55s.
Adding or removing washers from the inside will also help to move wheels in or out more, especially on Ace trucks as the hanger itself is not quite as wide as other brands, but the axle is still about the same (as others have said) so you can get more washers on the inside if you want to push the wheels out further, on any of their trucks.