Here's something to think about auto vs manual- the auto's TC does multiply engine torque over 2x for the initial few tenths of a second, then it gradually settles down to a little over 1x before the shift. Even though that it only lasts for a couple tenths of a second, it's that initial torque spike that you have to build the rest of the drivetrain to handle with an automatic.

On the other hand a manual trans does carry more energy into the launch with higher launch rpm, but it's torque input/output is much more even over the 60' than an auto. Torque input from a manual is initially determined by the clutch's holding power (engine torque + inertia torque), but you lose that inertia torque when rpm drops far enough to synch with rising vehicle speed. At that sync point the clutch locks up and the engine starts to gain rpm, so torque input then drops to whatever the engine puts out at that particular rpm and accel rate.

...600ftlbs engine x 2 for the converter x 2.54 for 727 1st gear = 3048ftlbs on the hit. With a 3.55 gear that's 10820ftlbs at the tire, but that 2x hit only lasts for a few tenths of a second.
...600ftlb engine w/ 800ftlb clutch hit x 2.66 for 833 1st gear = 2128ftlbs on the hit. With a 4.10 gear that's 8724ftlbs at the tire, and that hit lasts until the clutch locks up, probably around 0.75sec or so.

The net result is that you can apply a higher average torque over your 60' with a manual, without exceeding available traction or strength of the rest of the drivetrain.

Now that we have the ability to manage the hit of a clutch, you might not really need those big tires or D60/9" upgrade

Grant