Lots of performance places sell the turbo 400's but now they charge a ton of $$$. In the last 2 years I have been give 3 free turbo 400's. I rebuilt 2 as they had some issues, and the other one was a full manual valve body one that I got "free" and it works. Buy a core at a swap meet, go to YouTube and watch some videos on how to rebuild them, they're pretty easy to do inc. putting a shift kit in them. As for recommendations, Jeg's Summit and local transmission shops will have them, but without a core you will pay more. I know the 2 I mentioned don't need cores but it's built into their prices.