73 340 questions ....any help appreciated

You can just leave the top bolt out if you don't have the one with the hole or can't find one. You can just run without the drip tab and no top passenger bolt, as I've seen some built that way before.

It's better if you use the drip tab, but I would want at least three bolts in the camshaft thrust plate.

If you want to run the drip tab (and I would want to also), I would drill the thrust plate hole a little larger, then bend the anti rotational tab into the extra clearance of the hole so you can run the bolt in that hole without interference and not run the passenger side upper bolt. Then you can have three bolts holding the camshaft thrust plate in.

Here's a thread I wrote about assembling the front of a small block and shows the critical points.

http://www.forabodiesonly.com/mopar/showthread.php?t=287231