LS7 Valve Springs?

Are Z06 LS7 springs usable for the 3800 S2? I mentioned to a coworker about my new engine build and was looking for #105 springs. He said he would give me the used zo6 springs if I wanted them. This is what information I gathered from google:

Average free height: 2.311"
Average coil bind height: 1.291"
Average spring rate: 346 lbs/inch
Average pressure at 1.950" 109 lbs
Average pressure at 1.800" 158 lbs
Average pressure at 1.400" 300 lbs

Is there such a thing as too high of a spring rate? 300lbs seems like a lot...

the Z06 LS6 springs are the 90lb springs you can use. depending on which cam you are going with you may need a higher spring rate, but 90lb's work for most.
not sure if the LS7 springs are the same beehive shape needed to fit our motors.
too much spring rate is a bad thing. it puts undue stress on other components like timing chain.

I plan on using this:
Comp Cam Custom Grind Camshaft .050 - INT 210 EXH 220 .507 Lft +2deg

I dont know what +2deg actually means. That information is written on the CompCam box. My brother informs me that it is considered a mild cam. If my buddy brings the springs to work tomorrow I'll take a picture of the LS7 spring next to a stock spring.

I believe +2deg would mean 2º advanced timing. That's a mechanical setting that doesn't change. You can also control spark timing by tuning. Tuning would be the preferred method, as the amount of advance can be set and continuously adjusted for different RPMs.

The LS7's would be bad if they fit.

Install height on our heads is usually referred to as 1.800" which would mean those are 150+lbs at that height.

In reality our heads have less install height. With stock retainers ~1.72" and with LS retainers ~1.78". A machine shop I use mentioned some springs can gain 10-15lbs of force in that added preload.