The previous shortblock in my wife's 70 Barracuda had a cast crank. It held up fine to years of abuse, running 10s with Indy heads in a 70 Charger, and then mid to low 11's with 906 heads in the Barracuda. The crank is still fine, actually. It's the 1/3 of the LY rod from #7 that ended that shortblock. It exited out the side of the block and broke the starter off the bellhousing.