I am in the middle of building my 2001 4.0 stroker from a kit I got from Titan engines. The kit included Comp Cam 68-232-4 which they failed to mention would require stiffer springs. I have gotten my engine back from the machine shop and don't want to bring it back. What springs can I use on the stock head without machine work? Only thing I could come up with is the Magnum springs but I'm not sure if they will work on a 2001 head and if so what is the part number? Thanks in advance.