More power from my 360 Duster?

Aaron, most sites unlike the Lunati has links to the valve springs needed or have complete kits like Comp cams packages. Contact Lunati for the proper spring to be used.

On tire size, I would not change anything. That is about the size I would have recomended to start with. A 235/60/15 is a 26 inch tire. 26 inch is the size I'd start with. The 245 on a 14 is a tad smaller, but you can walk it out of the hole instead of slamming the pedal down to leave. A quick push of the gas pedal to the brink of spin will require a little practice.

A BFG Drag radial, (Or equal) 235/60/15 is what I would use.

A second 3rd member with the upgraded gears is a great idea and will not take to long to change out. I had it down to a sci. under and hour By myself from start to driving. (LOL, when I was good and fluid. Now I'm out of practice and rusty in the joints.)
This can be done a little faster and with a freind, easy at the track. Refill of the fluid takes the longest.

This will show up as probably the best change. (Gear ratio)
I like the cam, it'll work well with both ratio's.
You'll not need new pushrods IMO. Hyd. cams and there tolrences are flexable in cam changes. You should be able to swap out the cam and lifters without any problems.
The head should be able to handle the new lift. If not preped for plus .550 lift, your going to need to check everything out.