I would recommend using the early style timing chain cover and cast iron water pump, then you can use the original style power steering (if equipped), and alternator mounting, and radiator for an early a body with a v-8.
The later 318's had the timing chain cover with the timing marks moved to the other side, and aluminum water pump with the lower radiator outlet on the opposite side...
You will need to get a v-8 center link for your suspension so the oil pan will not hit the steering linkage.
I would also get a v-8 gas pedal assembly and all brackets and cable for a 64 - 66 a body.
What trans are you going to use? What shifter do you have in your car? Do you have the 65 floor mounted shifter for auto?
You may want to look into making yours like the 65 v-8 trans if you are going to run that shifter, it is a one year only item and uses the cable shift transmissions, not the 66 and later linkage shift transmissions...
You need to get your plan laid out so you can chase the proper parts/set-up...
