Throttle return and kickdown springs

Check the Help bubble packs at your auto parts. I have at least one with assorted "throttle return springs". The transmission kickdown slot spring serves double-duty as backup to the throttle return spring, so since you have another one on the carburetor itself, you are triple-redundant. But that doesn't insure your throttle won't stick open due to a sticky cable. Back in the day, drivers knew how to handle that. If you didn't "floor it" often, the accelerator pedal could stick. I had to sometimes kick it to get it to return in my 1969 Dart and fixed it by cleaning the cable end, fixing the broken plastic dust shield at the end, and a little non-gunk lube (perhaps silicone today). Worst-case, you can always turn off the engine and be ready to muscle the heavy steering wheel as you slow if power steering.

But, today we have people like the CHP employee in San Diego who sped around with a stuck Toyota pedal talking to 911 for 2 minutes before crashing and killing most of the family. Even worse with battery-cars which accelerate surprisingly fast from a stop. Today's accelerator pedals are just a "user request" like a PC mouse, in both battery and gas cars, so not sure that is any safer than a mechanical linkage which can stick, as they can become as erratic as your mouse. Re your "correct spring", good luck finding specs or a PN. Even if you do, are you sure what Chrysler spec'ed is the safest choice? At least your slant won't be throwing you thru any storefronts before you can blink, like the many Tesla cars you can find on the web.