Folks, I did as most of you suggested and machined the guides and seats on my Vortec heads. I opened the seats to 1.44" dia. and cut the guides down all with the Comp Cam tools. Now I have a question for you all. What springs, locks and retainers do I need? Please list brand and item number. I have a Lunati cam .504 lift. The card says 100 pounds at 1.75" installed height! I bought the cam and lifter kit and springs after machining the heads and found that the springs that I got are 1.26" dia. I installed them because Jegs guy said they would be ok only to find that the spring is moving around in the 1.44" seat! I then noticed a loud snapping sound coming from the valve area and found that the 1.26" springs are trying to jump out of the 1.44" seats. So, it appears that I need to install 1.44" springs and retainers but don't have an idea of what I need. I know many of you have done this set up and would like to know if you would share with me your success. Thank you!