Alexis_WK
Below are links to my dyno chart and dyno runs that shows HO vs 08 cams. Not exactly apples to apples as I also made the following changes between dyno runs:
Straightened, resized and smoothed custom CAI
Installed and tuned M/E Wagner PCV
Swapped HO cams for '08 cams
Installed new Comp beehive springs and Comp retainers
Ryan made minor changes to SCT tune as well.
Mods already done before HO runs (still installed for '08 runs):
shorty headers, custom built y-pipe and exhaust, custom CAI, 70mm F&B TB, WeaponX COPs, Flyin' Ryan Custom tune (frptuning.com), '08 intake manifold, Aluminum -6 fuel rails with return setup, Phantom Stealth fuel pump, clutch fan delete, 180* T stat, 25% under-drive pulley, TKO600RR, 4.56 gear, HHR fan. Long block is all original and stock with 93k miles on it. No porting.
The top 4 runs in the chart key are with HO cams. The last 3 are with additional mods listed in this message, with the last one with 3" cutout open.
Yours being a 4x4 and with already owning the HO's I would probably stick with those. There is definitely more power with the '08s if you chose to go that way.
https://photos.app.goo.gl/gKFcVHeoVu7ioigX6
As for the running the '08s on stock springs.....I checked clearances on coil bind with stock springs and was as little as .030"(=EX/.070"/IN/.030"). Depending on which building theory you use, that is "acceptable" to "not enough". My thoughts are stock springs are not anywhere near the quality materials that the Comp springs are and I would not choose to take the chance on spring/valve failure while already apart and doing the cam change. Also on the retainers, they are .033" shorter giving more retainer to valve guide seal clearance and CB clearance (now .100/EX, .063"/IN). Comp retainers vs Stock retainers 10.97g/8.75g considerably lighter and taking even more stress off springs and your old lash adjusters. Stock Spring weights are considerably heavier as well = Stk 4.755.18g HO springs IN=57.61g/EX=58.49g Comp 26113 springs =43.39g
Here are the dyno run videos as well:
https://youtu.be/V57WI8aF-FU
https://youtu.be/RbpvBJstYm8
Your mileage may vary!