I did my stock lower intake and heads and with the crane 2031, underdrives, long tube headers, offroad x, and magnaflow catback I dynoed 242rwhp 310rwtq.
A friend dynoed his '91 5.0 with e303, underdrives, shorty headers, offroad H, and flowmaster catback and got 211rwhp 275rwtq.
So say...