Like new Hurst from 98 wouldn't work in my 99, suggestions?

I got a deal on a Hurst Billet shifter from a 98 Cobra with about 2k on it. I attempt to put it on my 99 last night. It should pop right on, but it doesn't; it's offset by about 3/4" to the right. I finally get it lined up and begin tightening the bolts. When done, the shifter is frozen, won't budge.
Before I go on, I put shifters in my two previous 5.0s, so I'm quite familiar with the drill.
I loosen the bolts, and it shifts, albeit roughly. I take it off two times and try again, racking my brain why this won't work once tightened down. I finally gave up and reinstalled the stock stick.
Any thoughts you all have would be appreciated before I call the guy back.

The 96-99s had the T-45. The 01 has the T3650.
Tremec made the T-45 under liscense from Borg-Warner starting in '99, but if that was the difference, everyone with a 99 would have problems installing a new shifter.