What the hell is this thing?

[84_GT350]

So I'm under my car today and I notice something I never saw before. On the driver's side of the engine block right next to the crank pulley (but facing towards the fender instead of forward) I see this hole. It looks kinda like the exhaust port on a cylinder head...a rounded rectangle with a bolt hole on either side. Is this where a mechanical fuel pump would go? That was my only thought. I can't imagine what else would go there. And my car was originally a CFI car so there wouldn't have been a mechanical pump. I just figured if that were the case there would've been some kind of block off plate. Any ideas?

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1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s