Valve Springs!!!!! I know of alot of people that dont even think about these. Definetly key to performance. Especially if you want to run nitrous. Here are a couple of tools that make it easy to check and change them if need be. An example would be if you you a hydraulic cam you would want 90 to 120 lbs of pressure on the valve seat. Where as a solid roller could run anywhere from 190 to 300+ lbs on the seat. Check your cam manufacter for your specific needs. Also checking for full open pressure can help diagnose problems with the spring. IE broken or weak. These tools are priced medium to expensive and there are lower end models available depending on your application. The one tool I use on my engine is the LSM on engine spring removal tool. It bolts to the engines particular stud of the spring you are changing. Simple to use and saves time instead of removing heads. Just make sure the piston is at TDC when changing the spring as if you do not the valve could possibly fall into the cylinder thus need a head removal. Also a compressed air source for keeping the valve in place. When you have the spring out this would be a good time to measure the installed height of the spring. When you buy spring the manufacturer will provide the spring data with your springs. This is key so you can set up the correct seat pressure and determine coil bing of the spring. kmotion has a good tech article on their site how to set up springs. If you guys have any questions feel free to ask. Hope this helps.

Brant