cast aluminum, especially if it's ADC12/A383 is quite brittle, with maybe 3% elongation at break, with a yield strength of about 22ksi/UTS of maybe 30KSI. 6061T6 is much tougher and more ductile with 17% elongation at break, 40KSI yield and 45KSI UTS. that's not opinion, that's fact. hit a pothole at 40MPH and see which one breaks first.