whats this sensor in the power steering line for?

Shuts off the A/C compressor or even in some applications it increases the idle speed when the PS puts a heavy load on the engine, as indicated by the pressure in the line. It's usually only used on motors that have inadequate power for the car they're in, like a 6-cyl in one of these cars, or one of the weaker 305s.

ya..its a 305 tbi

Wow, never seen that one before. My 305 tpi did not have that. Strange how these cars are very similar and yet they all have very little things to set the apart from the factory. learn something new everyday!