I was hoping somebody would ask that question. There's a hole in the head and a hole in the block. It goes in roughly 1/2 way in each when you put it together. When you take it apart to do a head gasket, usually it sticks in one side or the other. Very rarely does it fall out on the floor. Tip of the day to not do what that guy did...look in the head and the corresponding hole in the block. You should only find one. If you find 2 or none, pull th heads off and find it.

Remember, on the 302, maybe some others, I don't know, the heads are reversible from one side to the other so it is actually very easy to end up with 2 dowels in the same hole. Hopefully you would figure it out before reaching full torque.

For now, a quick check is to stick your most sensitive finger on the seam between head and block and feel it all the way around. If it's up, you'll know it. The guy I'm talking about torqued all the way and the 2 dowls sort of mushed into each other The gap at the passenger side rear corner was about 3/16 of an inch. I know what you're gonna ask...I don't know how...Popeye arms maybe.