The Impala/Briggs in the picture above is quite similar to mine except for having a dipstick instead of a level plug. Base and colour scheme look the same. Seems like yours is probably later than 1976, since it has the dipstick, but it can't be much later or it wouldn't still be white I think. Yours has the same "Put your foot here, dummy!" sticker as mine. I have one of the small silver round mufflers screwed to the port (and it isn't very effective, despite looking new).
The state of your rear door worries me, it suggests that mine might rust too.
I take it yours has a Z-fold handle, the same as mine?
