After I welded new floorboards into my '86 245 I did a water test ...

after spraying water down the front vents and against the fire wall I found a couple of small leaks... feeling satisfied I went to bed with a fairly good strategy to fix a few leaky grommets...

next morning I go to put my bag in the back seat only to find the back seat floor filled with water (great swimming pool for a mouse!) we had received no rain that prior evening.

lo and behold the front was completely dry ... turns out the inner rocker panel right below the seat pedestal (and therefore unreachable) was also rusted through and all my water test water ended up on the floor of the back seat (never thought to look there during the test!).

in any case I learned the water from the front vents (right in front of the windshield) drains through the small drain holes in the rear of the rocker panels... slower than it drains through to my back seat floor...

question is ... could I drill a big hole in the front (just before the front door) of my rocker panels (underneath the car) to allow all the water to drain out before it gets to the rest of the rocker panel and ultimately my back seat?

a significant modification in Volvo's original design which I believe had some minor flaws.

whaddya think?