Not sure about hidden ones, I have a regular Reese truck hitch from Walmart. Paid like 115 bucks; said it didn't fit my specific truck but it fit so many other I thought no way it couldn't, so I bought it and it fit perfect, what're the chances...
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85' GMC Sierra Classic
Built 350; Weiand intake, Holley 600, Thumpr Cam
Built 350 turbo with shift kit & 2500 Stall
Thumpin' away