Cain, be careful when you do this, give yourself alot of slack in the adjustment at first. if you lengthen the pin and it doesn't catch, but then you push down hard on the hood and it does catch, it can be a problem to get back open again since it has all the extra force holding it down. Back the pin out a whole bunch at first. When the bonnet latches the hood will most likely then sit a bit high. Readjust it in little increments so you slowly pull the hood back down to where it is level with the fender edges, but not to tight on the latch mechanism.
I found this out the hard way once, had the pin to short and really smacked the hood down. It was way to tight and I couldn't get it back open again. A properly adjusted latch should open very easily without much effort pulling the handle and still line up with the body.