When these tire size/pressure labels first came out, the orientation was that the owner could look at it and use as a guide in purchasing/maintaining new tires for the vehicle. A consumer protection issue.
In that orientation, ALL of the available tire sizes would not need to be listed, just the smallest standard size on that platform of vehicle (to support the weight of the vehicle with good reliability and durability). Station wagons and their different tire capacity needs might have a decal specific to them?
The pressure listed would be more "middle of the road generic" than more model specific, which is in the owner's manual.
Back then, there were usually THREE tire pressure recommendations. The "stock, smooth ride/standard load" orientation usually was for 24psi. The "normal load/use" was a few psi more (as the "26psi" listed on many). THEN, there was the "max loading" psi listing, for the "full rated load" of the vehicle, 6 passengers and luggage. Additionally, IF speeds of over 70mph were to be used, to increase the psi by "4psi", but to not exceed the 32psi max pressure for 4-ply rated tires. All of this was in the FSM and Owners Manual. In the case of "Extra Load" (6 ply-rated) tires on some specific station wagon models (usually B-bodies?), then 36psi would be the max pressure.
Station wagons, usually were spec'd with a somewhat low front tire pressure and increased rear tire pressure, compared to the sedans/hardtops/convertibles.
End result is that starting with the basic 24psi pressure, if you drove on the freeways, you bumped it up to 28psi, per recommendations. For "max load", a bit more.
As a side note, in the pre-PMetric tire size days . . . I used that 24+4 orientation on our '66 Newport, for the rear tires. Then my calculations determined that for the front tires to proportionally carry the same relative tire load, I put +2psi past that in the front tires. This way, each axle/tire would support the same proportional amount of weight. This is the exact opposite of the factory-spec f/r pressure bias. But, handling became a bit crisper and front tire wear decreased as rear tire wear was "flat" rather than wearing more in the middle (from too-high inflation pressure). And that's what I started to run everything at, in that same orientation. The later fwd cars or some shorter-wheelbase "pony" cars might need 4psi (more than the rear tire pressure) to balance out their 60% frontal weight bias. NOT related to the factory recommendations, just my own experiences. Proceed at your own risk.
The higher pressures, tended to make the tire tread patch more "firm" and decreased flex as the tire rolled down the road. Keeping all tread ribs open rathe than otherwise, in all driving conditions. Much moreso with bias ply and bias-belted tires, than with radials.
Just wanted to mention these things to help with clarity on the tire pressure issues.
CBODY67
Well done, hope you're soon cruising the highways, like Easy Rider, get your motor running, head out on the highway.
