Just cleaned out the garage and found brand new Volvo 240 parts from IPD that I never got around to installing before I sold the car. I have both the Automatic Overdrive Solenoid Block-Off Plate and the Flame Trap Kit still in the plastic, both of which are common aftermarket necessities for 240s.
https://www.ipdusa.com/products/4793/110397-volvo-automatic-over-drive-solenoid-bypass-kit-ipd-110397-1239928
https://www.ipdusa.com/products/5317/104083-volvo-flame-trap-kit-aftermarket-3501707k
These are both free to a good home, I just prefer not to ship. These may fit other models too- just check the IPD website. Cheers!