Front yoke question

[57taskforce]

As you can see in my sig, I've got a '57 3100 sitting on an 88 k5 frame. I've a question about the front axle yoke. 10 years ago when I tore the Frame down for paint I had two of the u joint strap bolts break off in the yoke. Now that I'm finally getting back around to it I'd like to put the front drive shaft in. Can any one tell me the size/pitch of those bolts so I can get a drill and tap? It's a 10 bolt axle. I realize there's a blazer sub forum but I figure the yokes are likely the same between all the 10 bolt axles in all the trucks.