First of all, the JRSC is not interchangeable between LS/GSR/ITR motors. The 3 of those heads are different, so they have individual superchargers for each. So if your cousins friend had a GSR, it won't fit your LS. That being said, the JRSC on the LS doesn't make much power. I'm not impressed from the dyno sheets and timeslips that I've seen over the years.
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2015 Ford Mustang GT Fastback - Ingot Silver - 6M - Performance Package - Gibson Catback, JLT CAI, FR 47lb injectors, BAMA E85 tune, Eibach Sportline, BMR wheel hop kit, UPR oil separator, Steeda shifter bushing/bracket
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