Today I transferred 90 minutes of audio from a cassette tape from this the 1978 exhibit shown in this poster. I'm listening to it now, and I hear a voice I recognize... I think Maria Almonte is breaking it down. This is a real gem, and I hope to be able to share the transcript soon.
This exhibit was at the Chicago Cultural Center in 1978, curated by Jose Gonzalez- who also signed this poster. [He went to Harrison and graduated valedictorian in 1973.] I'm not finding much on Mexposicions 1-3, but I've just started to dig. More as it comes.
UPDATE: Linda Vallejo's website has 4 of the invitations from the events on her website. Lovely scans.