I didn't find the post about the A-518 transmission, but I save a record of all my posts. Here are the two responses that related to the installation of the A-518 transmission:
"I have an A-518 transmission in my Cuda currently. It has served me well for the last 3 years. The transmission bolted to the back of my 360 with no problems. I did'nt try to connect my trans-fluid lines to the radiator. Instead, I ran them to a separate trans-fluid-cooler. The fun comes in supporting the back of the transmission. The floor pans did not have to be cut or modified. I had to remove a U-shaped piece of metal that runs above where the cross member would bolt. This allowed the clearance I needed. In addition to this, I has to modify the cross member to allow the back of the transmission to mount about 2 inches below where the 727 would sit. Of course, the drive shaft has to be shortened a bit and the whole thing works very well. I've experienced no vibration or alignment issues. The original floor mounted shifter hooked up with a little modification to the shifter bracket that bolts to the bottom of the 727 trans. The conversion does require a little fabrication, but most of it is straight forward and self-explanatory.
On a performance note, the A-518 completely woke up with the addition of a Transgo skift kit. The car felt very responsive and crisp with the shift kit like a performance car should.
In conclusion, I would say that the benefits of having the overdrive along with the 3.91 gears by far outweigh the troubles with the installation. Interior noise levels are lower, better gas mileage and sustaining highway cruising speeds make the car much more practical."
After this post Chryco Psycho posted a response expressing concern about possible structural issues related to the cross-member and body modification. Below is my response to that post:
"You are probably right Chryco. Removing the U-shaped piece of metal above where the cross member bolts would probably weaken structural integrety. Particularily, if nothing else was done to reinforce the structure. I have not experienced any problems or issues that could relate to structural integrety in the three years that I have used the A-518 transmission. It is important for me to mention that structural integrety issues were anticipated by the welder/fabricator that I used to modify my transmission's cross member. He significantly beefed up the modified crossmember which is now a lot stronger and thicker than the stock cross member. Not only is the modified cross member serving the purpose of supporting the rear of the transmission it also reinforces the vehicles structure. This is probably the reason that the car feels as solid as it does."
I hope that this information is helpful.