5743015 is supposed to be a 230 block from 1963 - 1970 according to this:
http://www.guiaautomotrizcr.com/images/Aeraid%20head%20and%20block%20manual.pdf

Didn't know that GM was making blocks in Mexico back then...

Last edited by Gord&Fran; 06/13/2020 11:43 PM.

Gord 🇨🇦
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1954 1/2 ton 235 4 speed