I don't know any part numbers but you can try
http://www.4wheelauto.com/ (PH. 1-866-468-2570). They are the best place that I know of. I am bring in my first Hiace too but I have a Landcruiser Prado (2L-TE engine) and have got parts from them. Very fast and the best service I have ever had. My 91 Hiace has a 3L engine so I will be learning a new motor.
You can checkout my website with the infomation I have collected on the Toyota 2L-TE and 3L engines at
http://landcruiser.grundahl.ca/ (note I have not had time to make the site pretty yet but the info is there).Hope that helps.
J