Where is this interior leaking coming from?

[jzjames]

The floor and carpet continues to be wet whenever it rains hard.

I’ve just had the whole interior firewall stripped out, ( inst. cluster, ashtray, radio, wiper motor & assembly, glove box and heater box).
It’s not leaking through the wipers or the body seam that runs horizontally across the firewall. That is all sealed up.

I’m sure I don’t know where the water is coming in, and it’s a lot of water. Very wet.

The holes at the bottom of the windshield channel may be open to water, where do those drip holes drain to?