My fuel mileage is the same, maybe a tenth or two better.
Top speed? I have not done anywhere close to top speed capabilities.
As far as my saying the Tremec's 1st gear 2.97 with the 4:10s is more useful than the MT82/3:73s, the first time you are tooling around a parking lot, you'll see what I mean. There used to be times I was going slow in a parking lot and I had to figure if I wanted to stay in first at high RPMs, or go to second.
I don't have that problem anymore, I stay in first and the engine isn't screaming.
Yeah, that first parking lot you go to will tell the tale of a once again useful first gear.
Another member Kona stang10 did the conversion. Check out his signature below, see the 4:10s and the supercharger? He's doing 72 ft lbs more torque than I am.
"2012 GT Premium, Tremec 6speed manual,Ford racing 4:10's,Paxton novi 2200sl, Spec3+clutch, Whitleline lca,steeda adj. uca,Whiteline relo brackets, Sway bars, watts link, Steeda sport springs, Steeda hd strut mounts, Takico D-spec struts and shocks, Tremec Shifter, GT-500 Axle backs, kooks super street headers, S/W 3" off road x, Dyno tech d/s, JLT big Air Intake, Rev auto 93 dyno tune, Boss 19" 302 s wheels with m/t dr's staggered..641-rwhp, 557 ft lbs of torque."
2012 Shelby American Mustang GTS 580rwhp 485 ft/lbs Grabber Blue White Stripes
Ford Whipple, 5.0L, Tremec XL Magnum, MGW, Centerforce DYAD clutch, Boss 302 Torsen w/4:10s, 302R EPAS, Eibach Coil Overs, Fays 2 Watts Link, Dynotech DS, Shelby UCAs/LCAs, Wilwood brakes 6 piston 4 piston, Drake Bump Steer, heavy duty cooling, welded axle tubes, Interior Package, GT4 wheels, Borla Touring axlebacks, GT500 rear valence w/parking sensors, and airbag cover signed by Carroll Shelby.