Richard,the 2430-3030 designation is just the size of the maxibrake cans,meaning the dia/surface area of the pancake. I,m betting the 2430 is what you need on your truck.your sys. is what they called PRE 101 brake systems that ended at about 1971/72. the 3030 cansthat iv,e seen where usually on something as big as a 82 Mack R600 tandem 12yd dump
P.S. they also make 3636 cans. Regards Steve sr.
