What about using the brace on a high HP big bore build? Don't the big bore blocks only have 2 main bolts? Plus the two side bolts of course
Look into the JPC piece.. for a big bore Boss build, otherwise, and like has been said- above, its not necessary with the stock block.
My 5.4L iron block has 2 bolt mains with cross bolts/dowels. I'm shooting for north of 1000rwh, and 7500 rpm. I'm not worried for one second about my mains moving around.