Eric, yes, now that you mention it, I do recall the '74 140 fuel tanks were different. For 1974, the fuel tank was re-designed and relocated to a safer position closer and above the axle in the event of a full on front-rear crush, also designed with tank headspace to prevent escape from overfill expansion. The gas cap was moved from being recessed by the right taillight to behind the flap on the left rear quarter panel. I see a note that the filler neck was redesigned that year to include the fill vent tube.

Thinking of this reminded me that '74 was an introductory year for a number of new safety features and other engineering changes. These were among the reasons I traded in my sporty 122S for a brand new '74 144GL more suitable to my family and business needs. A few of these I remembered off the top of my head, but an early brochure I found reminded me of others: These included 5 mph bumpers (heavier, stronger square aluminum bumpers on retracting shocks), multi-stage collapsing steering column, SIPS (side impact proctection bars in the doors), stronger door arches, one-piece front door windows (no more window vents, but upgraded dash vents and now push button air vent controls), halogen H4 square headlights, and the BIS (bulb integrity sensor) bulb out relay we all know and love (Volvo was one of the first with this). 1974 also saw the introduction of the lower emissions K-Jetronic CIS (constant injection system) on the B20F, replacing the earlier D-Jet. The radio antenna moved into the windshield glass, not great for reception. A seatbelt warning buzzer was added with a passenger seat weight detector switch. '74 also saw rear child door locks and half-down rear windows, but I forget if those may have been 1973.

I remember I was also on a visibility safety kick and ordered Sun Yellow from the Halifax assembly plant, orange being too much for my tastes. My first upgrade was adding DRL with an aftermarket unit that used a sensor wire wrapped around an ignition wire to know when the engine was running. I got my first 100K high mileage badge without that car ever being in a body shop -other than my own rusty rear quarter panel, storage well and pinch weld repairs.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now