:bigtu thank you sirThose screws aren't anything special. It's stock Lightning T.B that's been ported. My plans had originally called for removing them, countersinking the head side, and installing flush screws. Then grinding what was left on the tail side off. That's doable, and especially compatible with all the porting going on. Just never got around to it.
When you take the stock throttle body off your truck, just use one of those screws. Or take one out of the one in your hand, go to a hardware store, (Ace is where I go). Most have a wall mounted device that lets you determine what the threading is. Once you find the thread size, go pick out four identical ones, and install them with blue Loctite. Done.