[Keith Seymore]

Oh good grief.

Maybe it’s simply a closeout and was never intended to provided access underneath.

Maybe the underbody structure is common across all models and the cover is what accommodates the uniqueness for your combination.

Maybe the engineer’s design was done and he “nailed it”, and then the studio came along and made a change to the seat that “they” (the Studio) wanted to fall on their sword over.

Maybe the engineer made a design change he liked and Flint Assembly agreed with it but the other six full size truck assembly plants couldn’t reach concensus.

Maybe the engineer made a design change that would work but it added one more bolt and the UAW wrote a grievance because the assembler complained he had to “work harder”.

Maybe the engineer had a requirement that the floor had to remain “backwards and forwards compatible”, meaning that he couldn’t make a change that did not allow the cover to be common across all model years.

Maybe the engineer wanted to make a change but his management would not allow it, because they thought it was not a priority or because it fell in the model year “red zone” where only the most critical changes associated with new product launch were allowed.

Maybe the engineer wanted to make a change but it would have added a penny or two per vehicle, resulting in additional cost of several hundred thousand dollars over the model year and the increase could not be justified.

Maybe the change would have resulted in additional tooling, causing several hundred thousand dollars of tooling charges for dubious benefit.

Maybe the same blank is used to create multiple detail part numbers and making a change would wipe out one or more of those subsequent detail parts.

Maybe a change to the cover drove a coordinated change to the floor pan, which is manufactured by MFD (Metal Fabricating Division). MFD cannot do rolling changes, since they are using the tool to run production, so in order to validate a change they have to create prototype tools to support preproduction builds, or part trials. The production tool is then taken down at the annual model change to finalize the design for production. Maybe management did not want to pay for a separate set of preproduction tools, or to entertain the change risk.

Maybe the engineer had bigger fish to fry, like working on wind noise, door fitment or durablity issues (cracks and breakage, or corrosion).

Maybe the engineer wrote the change documentation and the change got hung up in the implementation process and was never completed, and no one noticed it never popped out the other end of the system.

Maybe it was as you have modified it but it had to be changed back, because it cracked/leaked at 150,000 miles or couldn't be built that way at line rate (one completed vehicle per minute).

Maybe in addition to supporting the 1970 model year, plus current product support on the ’67, ’68 and ’69 models, maybe he was designing what would become the ’73 squarebody underbody structure (originally slated for 1972 model year) and simply didn’t have time to give it the attention it deserved.

Maybe the engineer wasn't even home, because he was supporting the '72 pre-pilot build in Fremont and the '71 pilot build in St Louis, and the 1970 model year ship had sailed.

Or, maybe as Tim suggested, it did not occur to anyone that 50 years thence one guy was going to complain on something called "the internet" about his inability to remove the cover seven or eight times in one day without having to undo 4 or 8 additional seat bolts.

My point is this: maybe the original engineer had a few more constraints to comprehend than you do.

K