battery leaking on the wire harness under the battery tray = problem
piston slap = problem
other than that not really, GM did alot of redesign on the car before they even started making production cars. like the oil pan that was redesigned a few times because they kept blowing up engines on the skid pad. they wanted to get all the bugs worked out they could before they started selling them.
*random note, the LS1 started the design phase in spring of 91'