i currently have an lt4 hot cam kit installed in my car, i was wondering would i need to upgrade the whole valvetrain kit to drop in a gm847 cam shaft, or would the current lt4 valvetrain kit not be sufficent due to the lift on the gm847 cam being far supperrior than the .525 lift.so perhaps i would need to only upgrade the valvesprings?thanks for the help guys.

 

You should be able to get by with only upgrading the valvesprings.
If you can, I would get hardened pushrods and new lifters.

 

You'll need a spring that goes close to .600 lift and can be installed in a 1.85 height , give or take a few hundreds.

You can increase spring installed height with keepers that raise the spring .050 and give you a few more options. they also make retainers that add some height as well. Make sure you install them at the recomended height!!!!