Arrow tanks not aerotank saddle tanks

[mrtoni]

So... after long last I finally identified these mystery tanks but input still welcomed. These saddle tanks came with a pile of nos hickey Parts and I assumed hickey made them. Low and behold I found the invoice and price sheet. Made by arrow tanks of placentia in 1982 for 70-77 blazers. 16 gallon under body rear fill each side. I don’t have a blazer currently but I know the ones with the side fill required cutting out the torque boxes right? It says “16 gauge rolled steel baffled located outside the frame rails forward of the rear axle. “
So.. is the notch for sitting atop the rear axle? Do you fill by rear bumper of in rear wheel well?
Help!!!