A855 - 5 Speed

@matthon
Glad the saga is over, and you got your refund. Thanks for sharing this with us.
My Roadrunner has been in the shop since June, getting multiple new systems, parts, and reinforcements done. Running, driving car, but multiple upgrades needed to be installed, some of those parts had been waiting to go in for 3 years.
I had an opportunity last October 2019 to buy a bunch of stuff for my Roadrunner and my wife's GTO that allowed us to check off almost all of the boxes of "things we want to do" to our cars. Wife gave the OK to put most on the credit card, and my bank account had a nice balance, so the ability to buy was there, the authorization was there, and the last day of the booths set up by the vendors at Cruisin the Coast meant the best prices I'd ever get, ever.
So to get to the point, and why I'm posting this in this thread:
I've had a Passon 5 speed for about 2½ years, and it works fine. I have (actually Passon has, my 833 since May of 2018, the third time I've sent it back to have a "popping out of 2nd gear" problem fixed that started after they did the initial work on it, which was over 4 years ago) an 18 spline a833 for backup, but only as a temporary way to be able to drive my car should the 855 require service, because I'm hooked on the 4.10 gears in my Dana 60 WITH an overdrive transmission. It's definitely a having my cake and eating it too situation. I have had a lot of work done to my car as part of this round of labor to get it ready for a 541 BMP aluminum stroker that I expect will be in the range of high 6XX to 700 horsepower and torque. That is supposed to be within the capabilities of the 855 to handle. Now that I've read through this and personally experienced having my 833 waiting for over 2 years for repair the 3rd time, needless to say I have no confidence that if I should need service on the 855, it would get fixed within any reasonable time frame and that would mean I'd be using the 833 standby transmission for a lot longer than I'd want to.
I've looked at Jericho and G-Force 5 speeds.
Can anyone recommend a 5 speed OD transmission that can handle high HP and torque (appx 700 HP/TQ) and do you know how much cutting or modification of a 70 Roadrunner is required to make it fit?
Does anyone have any comments about G-Force or Jericho transmissions?
Thanks.