[thatch]

Mike,
Thank's for asking. My version of the bottom water pump bolt is nothing more than a 3/8" coarse thread SS hex head bolt 4" long on to which I have firmly bottomed out a 3/8" SS nut. The nut now becomes what was the head of the bolt in the old system with the majority of the new bolt now allowed to extend slightly beyond the water pump cover. The threads left exposed are about 7/8" long which is just about perfect considering the thickness of the WP flange and the thickness of the accessory drive in that area. Just in case you're wondering, the two WP mounting holes are positioned to miss the idler and accessory drive gears, if someone were to install a bolt that was longer than needed.
Tom