some Duster gauges not working?

Hey everyone so I am having a problem with my 1976 Plymouth duster. I just swapped in a 340 from original slant six and am having issues with the temperatures and fuel gauges not working. speedometer works fine, horn and all other lights work and i dont have any blown fuses. i don't recall if the lights on the fuel and temp gauges work or if they are out as well. any help would be appreciated because i know nothing about electrical stuff.