No, that will have a different tuning. Also, as a general rule, you want less than an 1:8 width to height ratio for the port. What tuning and box size do they recommend?
Sorry, I hate it when people don't explain why something is wrong, or how to fix it. So what you need to look at is the area of the port. As long as you keep that the same, and the length of the port and volume of the box don't change, tuning will stay the same. Or at least close enough. But a really skinny port won't work well, hence the 1:8 ratio limit.
If you want to know more about designing boxes, and how changing the port affects your design, go to Facebook and search for WinISD. It is a free box design program.