I've done the 3.73 to 4.10 swap. It was one of my best mods to date. Just for a quick comparo, I raced a buddy before and after the swap. At the time I had stock heads/cam, but did have intake, rr, pulleys, converter, etc. With 3.73 I would pull him out of the hole, but he would catch and pass me before the 1/8 mile mark easily. After the 4.10, I would pull him hard out of the hole and he would never catch me. That is quite the improvement IMO. Well worth the $$.
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91 GT - Cobra Intake, FMS 65mm TB, C&L 73mm MAF, GT-40P heads, Crane 2031 cam, Crane 1.7rr, Built AOD, Art Carr 2400 non-lockup converter, Transgo shift kit, BBK cold air, FMS 'P' headers, Pacesetter off-road H, BBK pulleys, Flows w/dumps, FMS 4.10's, Steeda STB, StangNet LCA's, for now...
Original GT-40P Tech Page