Is there a way to use only 2 pins between the raspberry pi and arduino for communications?
On the Arduino side, yes. You can use any two pins and SoftwareSerial.
On the raspberry side? Ask your Ford questions on the Ford forum. This here is the Chevy forum where you can ask Chevy questions.
Specifically, I want to use python.
On the raspberry? You can't use it on the Arduino.
the arduino would handle raw data, and raspberry pi would interpret it
What does "handle the raw data" mean? Data from what?
What does "interpret it" mean? How are you going to get the raw data, whatever that means, from one to the other? Is that what the serial port questions are about?
and send commands and interface accordingly.
Send commands where? What the hell does "interface accordingly" mean. Useless vague terms like that will get you exactly nowhere.
namely, i will be using a tamiya track set, an ultrasonic distance sensor on servo, and perhaps a robotic arm, if i feel adventurous.
And what will the raspberry be doing? Acting as a counterweight?