Here's the stock cam in a ZZ4 for reference...
10185071
Hydraulic roller tappet:
Duration @ .050
I: 208
E: 221
Lift:
I: .474
E: .510
The heads use
12551483 Single spring, 1.78 installed height, 1.22 coil bind. 1996 LT4 Corvette, ZZ4, CT350/400 and ZZ383 engines.
The stock lift is already well over .480 lift on the exhaust side, with the LT4 springs a Hot Cam is usually right on the edge of what the springs can take with 1.6 rockers. .525 .525 respectively. It's done everyday though without problems. The caveat is to always check the retainer to guide clearance, never assume because "it's done everyday"
1.78 installed height - 1.22 coil bind = .560 gross lift - .525 Hot Cam lift = .035 Safety margin. Getting a little close for comfort but like I said people are out there doing it everyday with no trouble.
FWIW the ZZ383 uses the same springs, uses the GM 846 cam with .528 lift on exhaust side .509 on the intake. 112 Lobe centerline
BUT with 1.5 rockers. If you ask me that's the cam you need to use unless you
REALLY want that lumpity lump idle.
You can get a more lumpity idle by disconnecting the vacuum advance if you have one with the GM 846, I did it for a while in my ZZ383, it sounded tough but didn't run as well cruising. Hooked it back up and am enjoying the good life, my wallet thanks me.
Here's what the 846 sounds like....