will Series 5 550 injectors fit and work in a series 4 13b turbo?

 

Yup.
Depending on what year your car is though- if it is pre 87 1/2, you will have to bypass the fuel injector resistor pack, up in the front passenger corner of the engine compartment.
REALLY easy, just jumper the wires across.
You can do a search for "injectors" "impedence" and/or "resistor pack" and the like, on here to find out exactly how to do it.

This is because the 87 injectors were low impedance, and used a speerate resistor pack to up the impedance. The 87+ injectors are high impedence as they are- no need for the pack.

 

They will work if you change plugs and have the correct or corrected impedence (just as Bambam7 said).

 

Oh ya.. forgot about the plugs...
They are very common fuel injector plugs.. got a harness that I took the plugs for mine from a junkyard T-bird I think...

 

how many cc's are those t-bird injectors?

 

I took the plugs, not the injectors.
I don't know.