As far as I know both countries had similar regimes and roles during the war, and the economic situation in Spain after the Spanish Civil War was as penurious as other European countries.
Because the Salazar regime in portugal while being autocratic was also virulently anti hitler and anti communist at the same time
The portugeuse had played ball with the allies during ww2 providing significant naval and air base facilities to them while publicly denouncing both hitler and stalin
On the other hand with spain while they were virulently anti communist aswell they has provided a large degree of support to the nazis not only in trade goods but also supplying them with a spanish combat division "division azule" to fight on the eastern front
Basically the portugeuse were good all around and relatively friendly qhile the spanish despite being a potential postwar ally against the reds had supported hitler and diplomatically isolated themselves