Bougicord spark plug wires for 10v cars: https://www.google.com/search?q=volvo+850+10v-bougicord+spark+plug+wires&client=ms-android-tcl-rvo2b&prmd=sivn&sxsrf=AJOqlzXnpG8p-6Ke7VV1ft3FXM0XrJZn4w:1676589252149&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiZ0rvWlZv9AhXmmIsKHRSzB34Q_A...

If you haven't already, it might be a helpful to measure the voltage on the primary (low voltage) side of the coil to see if it's good. I would expect it to be > 12.6V with the car running. Also, it would be a good idea to check the engine grounds and battery ground cables are good, with low voltage...

For the Bougicords, this info is located here ( https://rwblock.net/en/resistance-of-ignition-leads-volvo-850/ ) "Resistance of ignition leads Volvo 850 Resistance of new ignition leads designed for Volvo 850 2.5 10V B5252S (Bougicord PN 6469): cyl. #1: 4,97 kΩ, cyl. #2: 4,47 kΩ, cyl. #3: 3,58 ...

Yes...Mahle is oem.