For 379 Pete with Low air leaf or Flex air suspension your laden ride height is 8.5" or 216 mm and uladen air ride height is 8.75" or 222 mm.
Air Leaf 12" or 305mm unladen and 11.70" or 297 mm laden.
Air Trac 11.38" or 289 mm uladen and 11.00" or 279 mm laden.
Low Low Air Leaf 6.75" or 171 mm uladen and 6.5" or 165 laden.
To check your air ride hight you need to measure the distance between the bottom of your frame rail to the center of your drive axle.
I think 359 air ride height will be the same as 379 if suspensions are same.