We have a 73 Dodge Dart Swinger that the piston blew a hole in the block not even a week after leaving a shop. Recently my husband found a 63 Chrysler slant six that came out of a pickup. He removed the original engine and replaced it with the 63 engine. We are at a stopping point now due to our original flex plate and torque converter not fitting on he 63 engine. The 63 slant six was manual transmission our was automatic. What do we need to make it work so he can put his original transmission on this 63 engine? He loves this car and ready to get it back on the road. Any help is greatly appreciated.