So there will be an inaccurate read if the transit used a different stick and tube. Manufacturers calculate how far up the sump a certain amount of fluid will be, then they design the tube and stick around that height. The tube sets the height the dipstick drops into the fluid, so there are a few scenarios that are possible.

Larger sump volume than stock - it will still read "full" or "low" at the same height but the sump will have more oil in it to make it read on the stick.

Incorrect position of dip stick tube - For example if too long a tube is used, the vehicle will be overfilled with oil before the dipstick will read full due to the dip stick not sitting at the right height to get an accurate read. Too low and you get the opposite, the vehicle wont have enough oil because it will read the level too early.

Incorrect dip stick - This will have the same effect as incorrect dip stick tube height, due to the stick being too short or too long.

So as Marty says - Make sure you measure the oil amount before you put it in, then you'll know if the stick is right or wrong.  

Hey Deano, for my two bobs worth. Just ensure you have oil pressure, as well as the sage words from Marty And Mark.
I always err on a slight overfill, as if the breathing system is working you should be okay

with some strategically placed allen head bolts to fill in some holes I missed when planning the dash!
 

 
 
 

Looking good!!!