Babyduece is using an auto. It's not possible to put a T56 or TKO in w/o raising/widening the tunnel. You'll need to set the engine at whatever height/angle will result in a good match between the angle of the transmission output shaft and the pinion on the rearend.
Yes, I am using an auto.....but I also modified my engine mounts to move the engine 1" forward to gain more clearance at the tunnel. You should be fine where your at. If you find the angle is a bit off, adjust it at the pinion to get your angle back.
I had thought about moving the mounts forward on the engine - it seemed like there was plenty of room. But I did a search on pics for these things and it seemed like most people tucked them close to the firewall, so I did that. I made my own frame mounts and had a local guy plasma cut me some motor mount plates to work with stock 3-bolt Chevy mounts. In hindsight, I would have more room for the stock bench seat if I had moved it forward. The good news is that I can easily move it forward if I need to.
Relative to the ground (level floor) mine is 3 degrees down, pinion is 3 degrees up, zero pinion angle. But... That was when I installed the 4-link. Ive changed things and have to re-set my pinion angle I think, the ride height changed a lil, maybe. Once I get the front end back on I will dial things in. JR