Can you use a RWD 4A-C water pump on a RWD 4AGE? Yes, you just need to file off a little of the timing cover ridge and you must also use a RWD rear pump housing too.
Can the RWD 4A-GE rear water pipes be used on a Small Port 4A-GE (100kw) motor? No, unfortunately they cannot, they interfere with the knock sensor on the block. (Work-around in the next section)
Can the RWD 4A-C rear water pipe be used on a RWD 4A-GE? Yes, it can, but it wont allow you to run the throttle body cooling. Same problem as with the 4A-GE pipes on the Small Port in standard configuration also.
Is there any way to keep the FWD alternator bracket when using a RWD water system? Maybe, but it’ll require some modification of either the thermostat input pipe or the bracket itself.
How can I incorporate a temperature sensor (for a thermo fan etc) into my RWD water setup? By using one of the thermostat inlets from the remote thermostats of either the AE82 or AE92 you can use the inlet pipe in place of the regular one which has a temp switch built in.
Can I use a FWD pulley on the RWD water pump? No, if you do the belts will not line up.
Do I need the proper RWD head rear water outlet to run the RWD water system? Yes, unless you do not wish to use the throttle body cooling part.
Can I use the front water outlet pipe on the head of a RWD 4A-C on a RWD 4A-GE instead? No, it will not bolt onto the 4A-GE head.
Can the bypass pipe leading from the front water oulet to the rear pump housing of a RWD 4A-C be used on a RWD 4A-GE setup? No, but it would probably be possible to shortern it to fit.
More to come, just need to think of some more. If anybody has any questions ask in this thread and I'll add the responses here.