Talked to my transmission guy-------
I drove a nice 727 with a gear vendors behind it. I tried to use it to split the gears while at full throttle. It's just not practical. The Gear Vendors would not shift unless you lifted the throttle slightly. Then you would have to shift it back down while upshifting into the next gear and then back up again and repeat. I'm sure some guy could do it after practicing long enough, but as far as making the car quicker. Not! The car was quicker and pulled harder using the 727 alone and then clicking it into overdrive at the end.
Top that off with the disappointing ratio of overdrive you get for all that money and driveline angle adjustment, and it's nothing I would ever want in one of my cars. A four speed automatic with lock-up converter of your choice is the only way to go. The lock-up used with a properly set-up, higher stall converter is the closet thing to a 5 speed automatic you can bolt into a Mopar at this time.
I mentioned this in another post; The GV does not shift particularly fast when using their computer thingy, but slam battery volts into it with a push-on/push-off switch,it is lightning.When slamming gears and shifting into O/D at WOT you will not see a break in the blackies, and it will chirp the tires at 80mph.
And you can put full power through it on the inshifts, but you MUST NOT back shift through it. So when you finish your run you must lift off the gas to outshift it and leave it outshifted. You do not have to outshift it for engine braking. You just cannot put power into it during the outshift. And finally, that computer also prevents the unit from engaging when reversing.Reversing with it engaged will kill it almost instantly;ask me how I know;$1200 mistake.
So to recap; With a 904GV, you can have 6 very nicely spaced full power upshifts.But around town it's best to leave it alone until cruise time.
I also think tho, that there is such a thing as too many gears for most streeters. I have to agree with the 3+1 autos, being a nice option.
And if you believe that the .78 o/d is not enough, remember that there is no reason to run 4.30s with this set up.
With the A999 ratios you could trap in 2nd over. This will allow 4.30/1.20 =about 3.55s for the same trap rpm, and the starter gear would be 9.73, compared to; 4.3 x 2.45 =10.54 in the regular box. Set up like this with the 3.55s, your street shift would be first, second, second od, third od.And cruise would be 3.55 x.78 =2.77! That would be 2160 rpm@65mph, locked up,with 28s.