Could anybody tell me if I need to pull off the head inorder to get to take the valve springs off? Then could anybody tell me where I could find good performance valve springs?

 

Try any of the reputable speed shops they will be able to set you up.
Why do you want to change them anyway?

 

No you do not need to pull off the head in order to cahnge valve springs. Places here in Indiana where you can probably find performance springs would be Schied diesel or Haisly machine.

 

I was told that the oem valve springs tend or sometimes cause valves to float and cause them to fall down into the piston.

 

From what I've learned at vocational school when changing the valve springs if you bar the engine over until the piston all the way to the top the valve will rest on top of the piston but not fall all the way through.

 

You can change the vale springs on the engine, Cummins makes a real nice tool for doing this. As far as valesprings go there are several different options available but not all created equal. PDW offers several options they can be seen here http://www.performancedieselwarehouse.com/850866.html

Doug