You did not mention what engine you have............
If your engine is original it will have the so called "early" small converter bore. This means a later transmission with the larger converter pilot will not fit. You need to find out the year of your engine or measure the crankshaft converter pilot bore. If you find a later transmission, you could have a custom converter built I guess
Also be aware that Mopar transmissions MUST fit the engine. The slant six, the small block series, and big block or 426 hemi engines are three different transmission cases
Also, if you want to use a factory floor (console) shifter you must have a transmission with the lower mounting holes underneath
You can see them here, the two small "eyes" at the bottom of the tail housing just behind the main case