Replaced the filler neck on the Mazda, had to deal with a crapton of expanding foam and some hard epoxy-thing in the process, and even SELF TAPPING SCREWS. all to sort out a gasoline smell, which turned out to be a missing EVAP separator (bulge on right side of filler neck).
thankfully this is all gone. Next step after getting it to pass safety is to get it ready for either a F2T or KL V6 swap down the road. That also means getting the exhaust welded back up. and (hopefully) fixing it all.