please dont take this the wrong way, but sound's like it would've done it anyways. something wasnt right weather it was the crank messed up or a rod that wasnt reworked right or reworked at all.
the biggest prob you'll have with running it at the track too soon would be rings not seating right, especially if they're oem type. then it'll start smoking.

it's alotta tedious ( spelling? lol i can build motors but i cant spell too good! lol) work to set up a motor right, but it's just what you have to do to make it perform well.