Overdrive Transmission for 630 HP motor

I have been speaking to several transmission shops, and obviously getting a lot of recommendations for the products they're selling. I'm all good with that, and appreciate all the recommendations not to run an overdrive in the car. Ultimately, that is what I am looking for. Several of the shops have recommended their 18 spline A-833, and that may be a good alternative (if I deviate from wanting an overdrive), as several of the shops have built them to handle 650+ horsepower.

Thanks for the information on the Gear Vendors product, as I have been looking at that for a while. Possibly a great product. I was less worried after reading about the product about my 630 HP breaking the unit, more just on it's reliability. I can read all the reviews they have on their sites, but hearing from real-world people makes more of an impact.

As far as putting a GM tranny in the car, that would be my last option. I don't have anything against GM or Ford, as I've built several over the decades. I would like to keep it as much Mopar, as possible.

Thank y'all for taking the time to respond to my post, and I appreciate all the recommendations posted. I definitely have some more research to do, but quite a bit of information to lookup, based on all the feedback.