x2 on the 212/218 comp cam. Awesome cam and it will lope .
bout 4-5 hours taking your time on the cam swap with help.
If you are around 90,000 miles get a new waterpump too. They tend to go around that mileage.
Also its a good idea and cheap to install a new LS2 timing chain.
Z06 corvette springs are cheap and will work with that cam.
You dont want to go more radical than that in that big of a vehicle.
A 2800-3000 stall will really help with that cam .
As said you dont need to pull the heads or intake.
Once you get the waterpump and front cover out of the way, you can unbolt the cam gear, then spin the cam a few times,... This will raise the lifters up and they have retainers that will hold them up while you swap cams, Just dont fart around, get the old one out and put the new one in ASAP.