hi there any help gladly welcomed i was out in my s1 transplanted xr i was'nt going that fast when something went pop thought i had ran over a tray of bolts.i stopped {oil and water }everywhere pieces of casing i believe this to be the block why has this happend and what other block can i use just been put 2 gether head skimmed all belts changed etc what damage may have been done what do i need thanks