Cutting Guide Plates
 

If I cut guide plate for allignment resons do I need to weld them back together or will they stay put from the rocker stud tension.

a lot of people don't weld them, making sure the alignment is correct after the studs are torqued. There isn't much side load on them so they should stay where you put them. But it doesn't hurt to be safe.
If I have that problem when I reassemble my engines I'll weld them as Sutphen recommends.

I guess you can weld them and get the hardness back that way, but if you are breaking guide plates from rocker side loads you got other problems. Sounds like you've got valve train geometry problems. You should not be breaking them unless your pushrods are bending from higher spring pressures or your rocker alignment is way off. Are you using a quality 7/16" pushrod and a good HD guide plate? I guess anything can happen but I would check things out .
Raylar;)

Raylar, he's cutting the guide plates to correct a rocker arm/valve stem alignment issue caused by the guide plates.

If the guide plates are causing an alignment problem I'd go looking for a different set of plates.

Yup, you can do that. Comp Cams supposedly markets guide plates that take care of this alignment issue but it's still no guarantee that the roller rockers are going to be aligned all that well with the valve stem. It's not that big of a deal to cut the guide plate. And it's almost free.

All it takes is a little time