Hello Vstol,
This sounds like your clutch is not engaging. Are you running hydro set up or mechanical clutch set up?

T56 take out from a 1994 Camaro. Chose it because it mated right up to my one piece rear main seal SBC and it fit right into my trans tunnel with just a little hammering.

With a 350 rear gear and 25.5" tire it works out great, plenty of close ratio gears down low and will cruise at 80 mph at 1800 RPM in 6th.

I probably thought about it way too much. I knew I wanted a new Magnum for strength and I was already planning to cut the tunnel for easy of service. I loved driving the car with the Muncie for so many years (with 4.56 gears) that I figured it would be fun to pick a transmission and rear ratio somewhat close to the original gear ratios. I know it is weird but I used to enjoy starting in second and then just shifting straight to fourth with the deep rear ratio. I built a little gear calculator and messed around with the numbers.
The wide ratio (TUET11012) first four gears lined up closest to the original Muncie wide ratio gear ratios, coupled with the new 3.90 rear gear.

Then I looked at highway speeds and figured I want to cruise the heck out of this car and the roads are long and straight out here in the west. It was easy to select the wide ratio with the .5 final ratio to keep the RPM below 2,000 at 75 MPH.
If the car runs out a steam too early on the Auto-X then I can always select a higher gear ratio like 3.70 or 3.5.

http://i.imgur.com/MlCTxERl.jpg

Hyd clutch and looks like I got it thanks

TKO 600 cause I wanted to be able handle any kind of engine I threw at it plus I wound up getting a killer deal on one with 600 miles. 25000 miles later still running strong.

This is a great gear ratio calculator:
http://fitbodyshop.net/gear/index.php

I love the close ratio 5speed TUET11009 with .63 overdrive. Select CTSv Gen2 on that calculator for these ratios. Otherwise just input the gearing manually. The gearing is just about perfect as you can see by the graph and chart. A little more overdrive would be nice... one rarely uses 5th gear on a road course anyway and 1-4 are awesome ratios.

Thanks for posting that up. Wish I had found that before to save a little time and a few brain cells - nice calculator!