Spent much of my career in materials management Will try not to get long-winded.
Every model year [MY], Sales, Marketing and Operations have to do a Sales and Operations Plan [SOP]. First thing, how many of these cars are we going to sell? That determines the capacity of the manufacturing plant(s), determines a master production schedule and drives a forecast for component material requirements. From there, planning drills down to how many coupes, converts, 6 cylinders, 8 cylinders, transmissions, etc. Each component, common or optional, has to have a plan. The plants that supply these components will produce based on this plan. Some parts will be in continuous production [base engines, etc] some low-volume stuff will be produced in batches to be held in inventory at the assembly plants. Some special components were supplied only when specifically ordered [M22s, ZL1 engines]. I have read that the demand for Z/28s was well over forecast, greatly exceeding the capacity of the plant that produced engines. That meant there was virtually no room for error on releasing Z/28 bodies out of the bank for final assembly. In those days, I doubt the systems did any kind of material-assurance so someone had to ensure engines were in stock before releasing a body from the bank.
The second consideration is as noted, striping. The final assembly line had to balance; they could not run back to back higher labor content units like RS or Z/28. So maybe every 10th or 12th car down the line was a Z/28 to keep things balanced.
Just for the record, bodies were assigned a VIN as they entered the bank. Cars were not built in VIN order. There are sequentially VIN-numbered Z/28s and Z11s; they were not final-assembled together.
