i just installed new springs on a set off vortec heads, i machined the spring pockets down to accept a 1.440" dual spring, i machined the valve guide and boss to accept the dual spring and a .530" valve seal, the issue im concerned with is when the springs are installed the bottoms arent centered on the shims, i can move them around by hand, never done this to heads b4, but i got em for 50$ off a 30k mile tahoe that been rearended, so i figured i'd save a little and do it my self, i had a concern with machining the pockets to far, so i cut them to 1.440 and didnt go below deck, or do i need to cut them down into the head to create a lip to hold them in place? or is this no prob at all??

 

If the guide was machined to the ID of the inner spring it will hold them centered. You should check the installed seat pressure (amount of lbs that moves the valve off the seat).

 

Installed height should be checked but it also sounds like you need something like this

http://www.jegs.com/i/Comp%20Cams/249/4694-16/10002/-1