i need some advice. i know someones got 2 know the answer to this. ive been working on my 1978 jeep cj5 for over 2 years now and its almost done.im having carb issues. it wont idle. it sounds real sluggish like its getting too much feul.well anyways here goes the question. ford motorcraft model 2100 for a 304 *** 5.0 liter is 180 bucks, same model carb for a 302 5.0 liter in a 1970 ford f100 is 80 bucks. whats the difference? can i go with the f-100 carb? will it work? please email me @ jledley@hotmail.com if u can help...thanks. i hope i came to the right place.  

The difference is probably emissions, and a manual or coil spring choke. if it will bolt on it will work, make sure the base plate covers the intake surface to avoid any vacuum leaks. the base from the late model may even bolt on the early. the late model carb may have an altitude sensor something along those lines for mileage and emissions control.
I don't have either carb handy but that's my thought.