The previous owner removed the EGR completely on my 5.7 TPI car--absolutely nothing remains, even the EGR passage in the intake is blocked off.

Would it be worth the trouble to scrounge up the parts to put it back on the car, or would I be better off leaving it alone?

I'd prefer to put it back, but noticed a couple of things...some of the parts aren't available any longer.

If I was absolutely set on reinstalling the EGR, what parts would I need, where could I find them, and roughly what would it cost?

 

Off the top of my head, you'd need:

1. EGR valve - local auto parts store. Some catalogs kist two different ones. You'll need to know if the original was either negative or positive back pressure (most likely, it was a negative back pressure model).
2. EGR solenoid - NLA. Wrecking yard? I think you can use a later model solenoid if you splice in the corresponding electrical connector.
3. EGR temperature sender - NLA. Wrecking yard? Someone may have a NOS or used one for sale
4. Vacuum harness - NLA. Wrecking yard? You can make your own with just vacuum tubing or tubing and Dorman universal hard line.

 

Just an FYI: Not all years had the temp sender. Check application before spending money on it.