Clips for fuel lines at the fuel pump.
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Junkyard. Although, it would require dropping a fuel tank to get at them. Or you could bring a cordless angle grinder and a cutoff disc and cut a hole in a truck bed. << I know my local junkyards despise of that on salvageable truck beds... so be wary or at least choose a bed that you know isn't really feasible for them to make profit off of...