i'll try too calm your nerves a little , white smoke means your eating some water, its not oil. if you screwed up the honeing in the cyl or anything to do with the rings you would be shooting out blue smoke. Because it happens at wot i would guess its because for one reason or another your head gaskets are leaking under hard load. i would try retourquing the heads first, and then see what happens. did you re-tap all the head bolt holes in the block before you put the heads on ?