The current study presents the delayed naming task as an effective tool for testing the robustness of phonotactic constraints. A delayed naming task was employed to test for quantity sensitivity among nonwords in Spanish. Results reveal a robust effect of stress modulation by syllable weight as evidenced by differential rates of error between penultimate diphthongs and monophthongs in nonwords marked for antepenultimate stress. Items containing phonotactically illicit diphthong/stress combinations were also shown to improve significantly over time, showing that the cognitive constraints on proscription can be overcome with sufficient preparation time. Rising and falling diphthongs were also shown to restrict antepenultimate stress differentially, replicating the findings of Shelton, Gerfen, and Gutiérrez Palma (2012) and revealing sensitivity to gradient weight distinctions in the lexicon. These findings offer further evidence in favor of nuanced quantity sensitivity in Spanish and demonstrate the utility of the delayed naming task to view phonotactic processing over time.