904 not shifting into gear

I had my transmission completely rebuilt with a performance shift kit and custum built torque converter a couple of years back. I finally got to the point last week where the engine, transmission and driveshaft were all in the car at the same time. I ran the car up with it on jack stands and figured I would break in the rear end while I was at it to Moser's specs. The transmission shifts from park into reverse and all work fine - tires turning in the right direction and everything. So I shift it into drive and nothing - rev up the engine - still no rotation of the driveshaft or rear wheels. I am not a transmission guy so I left it at that. I am 90% certain the linkage is hooked up properly and moving the gear selector lever as it should on the transmission.

Is there some easy checks to make to try and track down the problem? I will run it up tonight and see it I get anything by shifting it into first or second as this did not occue to me until after I was done mucking around.

Another thing is - the car wont start with the transmission in "neutral" I though this was an issue with the neutral safety switch so I tested it and it didn't seem to work so I replaced it and retested it and got the same failures - ie center post is grounded in park - but not in neutral, and there is no connectivity between the outer posts in reverse - so this leads me further down the thought path that the transmission itself isn't shifting even though the selector lever is moving.

Thanks in advance guys.

Bryan.