You can just block all the ports if you're not connecting the heater?
that's debatable, and conditional to weather or not there is a way to fill the system with water.
some systems fill through the heater circuit.
I would suggest a schematic for the model with the accessories for system being worked on.
on the 69/70 models with no A/C I have seen. there is an intermediate tee piece in the bottom radiator hose that is plumbed to the expansion tank on the guard.
This system has no fill point on the radiator tank, and is filled by this tee piece in the bottom radiator hose via the expansion tank, the expansion tank is vented to the inlet manifold water heater fitting to bleed air from the system.
there is also a air bleed from the top of the radiator to the expansion tank ( 3/8" hose I think )
its worth noting that there has to be a continues bleed from the radiator tank for the system to work correctly.
if there is no vent on the top of the radiator, air will build up in the system and reduce the effective cooling area of the core.
one needs to be 100% a where of just how the cooling system works before modifying it .
its not just a mater of the water going to the radiator.
bfit
