It's amazing that car lasted 40 years with the EGR thermal system. They caused the heads to overhead and crack. Also amazing that car still appears to have the EGR plumbing in place. Lots up people updated the systems by removing; I did this on a 1975 530 (great car), and it ran fine. In some states the car had to have the system intact to pass visual smog inspection though.No one wants a 78 with thermal reactors though, 79 has lambda with a cat.