MacNoob, you´re right. It is a heater core. My dad told me after he checked better the car.
Iwas cleaning it and it struck me that the honeycomb was way too dense to be from an
oil system. I ran some solvent and old oil to check the flow and it would pose no problem, I think.
Either way, I scraped the ideia to mount this one, it´s a bit big.
I´m trying to source something like the old vfr,cb,cbr hondas had.