just had motor rebuilt by shop, and after 1300 miles [break in period at 1200 miles] engine block blew the F*** open, now there is a big hole in my block. so my question is what he hell happened. i was just driving [my 5th and 2nd gear pop] in 4th gear at like 5000 rpms i had been told that driving in 4th cant hurt me or can it. what do you guys think happened. everything checked out oil,water, everything...by the way dont go to a machine shop that has to ask, "a b18a whats that, is that one of those jap engines". just so you can save $200 bux not worth it.