The stock ratio on LS1s is 1.7. I doubt you'll find any 1.6 for an LS, but if you did, you'd get less valve lift. There are some 1.8 and 1.85 rockers out there, but I'd advise against them. I don't even like aftermarket rockers in the stock ratio.
Other than the needle bearings escaping, the stock rockers are pretty well-designed pieces, and they're light, which is critical for a stable valvetrain. Going with heavier roller-tips and especially to a higher ratio will require better valve springs, and even with them, the probability of valve float increases. Also, most of the aftermarket rockers are made of cast aluminum and have a reputation for breaking.
Too much risk for too little reward IMO.