Volvo did have quality control issue with the original camshafts in the '74 B20F's. Made for things like noisy valves, worn valve guides and smokey rear end under deceleration. Depending on the mileage, it's very likely that's all been replaced by now. Valves still need regular adjustment though.

The mechanical CIS K-Jet system is extremely reliable in my opinion. As the 74's didn't have an in-tank pre-pump, they sometimes suffered from vapour lock-type stumbling and bucking, especially as the main pump got older. I'd upgrade the in-tank sending unit to a 240 assembly. Other than that, I never had a serious issue with the fuel injection system in the 15 years I had my '74.

Rusted body panels were the biggest issue for me. The usual: rear storage well, rocker panels, wheel well fender seams, pinch weld around the trunk lid.

Other than front suspension and steering, if you are acquainted with 240's, you'll find the 140 very familiar territory.

Oh, almost forgot, if it's still using the original windshield in-glass radio antenna then be sure to replace it with a proper fender mounted one.

IMHO the '74 was the best year for 140's, possibly even more reliable than the early '75 and '76 240's.