Jeli, kamele or donso?
If its a kamele/donso you may need a new neck as the wood used for traditional ones doesn't have to be as thick or as hard, and it may split if you drill it to enter the heads or maybe too soft to take the screws...
You just need reguler machine heads, its important to realise though that you will lose alot of the nice feel as you are substituting having the string pressed against the wood either with skin like a kora or most probably with rope.. and depending on which type of neck you use there may be no contact with wood at all i.e. nylon against metal which to be honest I am getting tired of and am thinking of going back to traditional or at least have one of each.
here is an example of wht i mean, while its a thing of beauty the string doesnt conect to the wood
http://www.baragnouma.com/ngonis.phpYou can also make wooden pegs..
The best type of neck is a dug out one, which will mean a bit of carpentry..
Stick up a picture and i will let you know...