[Greg Reimer 7376]

The boat engine that blew up was a 71-72 402 short block with a cast crank.He put that in the boat while his good 427 was down for a rebuild. Boat engines, especially in the Colorado River water ski crowd, tend to come out of the water, free wheel,land hard,load the prop hard, climb back out, ad nauseum. There are continuous shock loads thrown at the rear of the crank interspersed with as many total unloadings of the prop. This continuous twisting and untwisting of the crank is what blew it up. It probably was cracked to begin with.
I think the original question in the first part of this thread was wondering if a steel 350 crank would be OK in a 305. We're assuming OEM parts here,yes it would work.Any balance differences between 350 pistons and 305 pistons would be easily taken up in a normal balance job.