Can somebody tell me real quick which is the inlet and which is the outlet for the coolant system on the engine block?

I looked in the shop manual but didn’t see anything that alluded to the coolant flow path, but a mechanic (not familiar with 7s) told me it would probably be the higher of the two would be the exiting coolant from the engine.

 

Correct In your picture the Waterpump draws water in at loc 2 (water pump inlet) and it exits the engine at loc 1, (top of thermostst housing).

Usually the system is set up (all cars not just rx's) so the waterpump draws water from the LOWEST point of the system (usually the BOTTOM of the Rad) so even when the system is low on coolant it can still draw the remaining coolant up to the engine.

 

“so even when the system is low on coolant it can still draw the remaining coolant up to the engine.”

Thank you maxpesce I hadnt considered that.
The only reason I ask is because I am building a vmount setup like Chucks and would like to keep the left side of the radiator cooler (by the airbox) than the right side, so I am going to try running the coolant in on the right and exit on the left. Even if the heat coming off the radiator is insignificantly cooler I would like to keep that area as cool as possible.

 

Remember that the EXIT side of the RADIATOR is the COOL side,
I dont think the STOCK style (vertical flow) rad is the best for a V mount - I would go with a CROSS-Flow style Rad w/ the exit on the pass side (near the front / Low point) and the inlet on the drivers side rear/High point.
For even better cooling i would suggest a DUAL Pass setup w the flow going from an inlet on the drivers side rear to the front header tank then back through to the Rear on the Pass side.