Hello Lcaruso,
As far as I know there is no top limit, I mean certainly there should be a boundary but I have not seen it before so you should be good ( On the FWSM we do have limits, on the ASA as long as your memory supports it we are good )
Regards
Julio Carvajal
Senior Network Security and Core Specialist
CCIE #42930, 2xCCNP, JNCIP-SEC