doing a swap on a 67 gt with a 225 727 auto trans - to a 170 2 barrel using the same 727 trans. What do I need to have for the linkage to hook up correctly? What size and make carb will work best?

If you really have a 727 auto trans in that 67 Dart and you have a 67 and older 170 SL6 engine, then you have a parts combination that will not go together.
(all 727s have a "big hub" converter nose and all 60 thru 67 170 Slants have a small pilot in the back of the crankshaft)

If the Dart really has a 66-67 904 AT, then it will all go together with an oil pan / pick-up tube swap. (if the 170 is 60-66)
You may need to adjust the exhaust pipe because it will hang lower when installed onto the "shorter" 170.

You will need factory Super-Six linkage or a Locker cable kit... and some fab time, in order to get the throttle pressure working.
DD

Is there a way to hook up the manual trans and still keep my gt center console?

You'd probably have to sell it and buy a stick shift console....but thats just one of 50 different things you'd have to do to make it a manual.

Try and find a 904....they're dirt cheap.