The crank won't be your problem it will be the block. The 2 bolts are stronger but they are all questionable. Do a search on here and SPEEDTALK there is a lot of info. As far as the steam holes I always just drilled them in the heads I was gona use...but I only messed with 400 sb in a street /strip application. I've built 2 of em with factory blocks but compression was never over 11 to 1 and power was 500 or less I'm sure...also was a 72 Chevelle.
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