crane cam

That is an older Crane grind. I am very partial to Crane products. They are not always the fastest ramp, but Crane has really taken the approach that street engines love. Flat torque curves and very strong mid range HP. If it were me I would be looking at something like the 693801. It has more lift and duration on the exh side, a little less lift than the .480, but I think will be a great match for the Magnum 1.6s. As far as springs... There are a lot more choices in LS1 beehive designs and they are a better quality part than the MPs. On the rpm of valve float... If the setup is correct it is very easy to determine when the valve float will crop up. That rpm is assuming you have everything set up properly and run the crane spring. A side note... Crane generally recommends lighter springs for thier cams when they are compared to similar other grinds from other makes. Engle did that too.