Will GM 200r4 work with factory floor shift location?

Well I finally got my mechanic to install the 3.73 gears into my Barracuda. Unfortunately he said to cruise around at varying speeds for 100 miles or so before I stomp on it. I'm looking for two things: will I get enough low end response off the line and how will the lower gears affect the WOT shifts with my new (modified) 2004R governor??? I might be barking up the wrong tree because I just received my 15X12 polished rims (15x12" Weld Pro Star Drag Race Wheels) for the rear. I'm planning on running these tires:

[ame="http://www.ebay.com/itm/Mickey-Thompson-90000000225-6642-Sportsman-S-R-Radial-Tire-29x15-00R15-/161135662386?pt=Motors_Car_Truck_Tires&vxp=mtr&hash=item25846f1532"]Mickey Thompson 90000000225 6642 Sportsman s R Radial Tire 29x15 00R15 | eBay[/ame]

now that I have the rims. These new tires are about 3 inches taller (1 1/2" per side) and may further affect my WOT governor response. We'll see?????

Treblig