First off is there another spring out there that would support a .600 lift solid flat tappet cam that would work with no machine work? What machine work would be needed to use the Isky springs on stock iron heads? Spring seats, valve guides etc? Also please recommend retainers and 2/4 groove locks for these springs. As always thanks for any and all comments.

Assuming you are looking for an installed height around 1.85" and have 0.600" at the valve then Comp double spring part number 950 will do the job with 149 seat and 349 open or single spring part number 911 with 141 lb seat and 365 open. I'm sure there are many more but the chart in the Comp catalog makes finding a spring too easy.