all you have to do is pull the coils and valve covers to switch springs and pushrods. Get some CompCams 26918-16 springs and 7.400 CompCams or ThunderRacing hardened .080" wall pushrods. There's a guy on LS1Tech in the tool section that markets an inexpensive spring compressor tool, about $20. An air compressor tool to hold the valves and you're ready to switch springs. I'll take the spark plug out, put some cotton rope into the cylinder(leaving some hanging out to retrieve it) and the rotate the piston around to TDC to lock the valve in place while swapping springs.