6. Here’s a nice touch for old-school racers. The LS family of engines use metric fasteners. RHS has spec’ed top shelf ARP bolts for its block, but with a bit of a twist. The threads are metric just like stock, but the heads are sized to accept SEA wrenches. Also notice the multiple bolt holes for mounting the block. This unit will bolt right up in a car with standard small-block mounts. Small-block and LS engines also use the same bell housing bolt pattern.