Both the 7401 and the 7403 are rated at 7 V maximum output off voltage. Source: www.ti.com datasheets.
Sorry, my bad, went to look at the paper copy of the TI datasheet, and yes, they are 7V rated, I was thinking of the 06 and 07, which were 30V rated for the outputs.
Funny thing is the rest of the chip is still only rated for 7V, though you will find that many will work at 10V with nothing other than running pretty hot. Got a wall ornament board where that hapenned, the power supply decided to apply unregulated 14V to the TTL, and the only IC to fail was a SFC5406PM3 30V capable open collector gate, which was easy to find, as it had unsoldered the can of the flatpack lid.