Some carbs has a solenoid to cut off idle circuit when engine braking. It is not perfect solution though as fuel can get drawn from power side, but in theory there were means to have a fuel cutoff. Quite short lived invention I believe as injection systems were already very close by the time.
Yeah, but its still worth a mention that carbs should work a little bit different other than "making less power" and "not having an RPM cutoff". Having all these nifty things would be nice with, say, the carbed covet since it would be the last carbed car in the timeline on beamng. But it IS something to fix with older carb cars.
It was still an old indirect injection diesel instead of a modern TDI. So its still gonna work a little bit different.
Fuel injection that injects to manifold versus direct injection, that is similar way bit different working among gasoline engines. Then there was mechanical fuel injection, which is very similar to older SDI diesel technology, but of course diesel and gasoline are different.