Originally Posted by skidmarkbass
No, I don't plan on putting on a different neck... Still using the 5 string neck and changing the nut.
If you want the bass to play and look nicely, you have got a lot of work to do.
Defret -> trim both sides of the neck -> cut some 5 plugs, glue them into all tuner holes -> thin the peghead and layer it with veneer, or paint it (front and back parts) -> drill 4 new tuner holes -> refret -> carve the neck -> refinish the neck -> level and dress the new frets.
I'm assuming that this is a cheap bass that you can trash.
I said that because I have no idea about how experienced you are with power tools, like router.
You can definitely mess the neck up completely.
On the positive side, if this will be your first mod, it would be a good and interesting experience for you.
You will never know if you didn't try...
All the best for you.