You could find a Plymouth cross member ,,, install the motor and attach the CM so you will know where the install the CM.. you may also need the Plymouth linkage because the motor is going to be setting closer in than the dodge . This all could effect your drive shaft . or you could make an adapter to go from the Dodge CM to the Plymouth bell housing but you will still have to deal with the shift linkage .the pictures show the adapters that were made by someone on this site ?? . you could also use a 230 bell housing and it would bolt right in but you would need a longer input shaft for the transmission and a longer throw out bearing shaft also . i think a 56 Plymouth had a setup like that with a longer input shaft so they could use a standard or automatic transmission with the same setup. someone on this site did that but i can`t remember who .