I posted before what a PITA it is to replace the early vent gasket. I hadn't realized that the 25 and early 40 were not bolted together. It is posssible to work/grind/melt/pick the old gasket out and coax/squeeze/beg/beat a new one back in............I spent a couple days doing that before............................new method:
Here's the offending vent with it's spotwelds and without:
Here's the offending vent with it's spotwelds and without: