I want to change from a fuel sender with a float on an arm to a verticle type sender does anyone know a seller of that type of sender

We got our VDO dip tube sender from www.spiyda.com, he even modded it to the required length and also does a nice little box of tricks to help in calibrating it. Highly recommend him.
HTH

Merlin Motorsport are competetively priced for VDO. or Egay.