Originally Posted by 46Tbird
The Aluminator has pretty tough internals, but the coyote blocks will deform and break in the water jacket with too much cylinder pressure. There are a couple of aftermarket solutions for the issue - good ol' block fill, or some kind of goofy reinforcement running the length of the cylinder bore, and there is talk that Ford will release a couple of different blocks for high-hp coyotes.
This is the 'Coyote HO' block from Ford Racing: http://s197forum.com/forum/showpost....1&postcount=26
This is what can happen when running a stock block.

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That is what happens when you push them over 1000 RWHP for a while.
Even the new FRPP Test Block did the same thing on Jon Lunds car.