I absolutely hate all the shifting these new fangled trannys do! 8 gears is about twice what they need. These modern engines are made to make more TQ over a far broader range of RPM and they can E A S I L Y make enough TQ to work with a 4 speed auto from zero to 200 MPH with appropriate ratios.
And to keep things as simple as possible, I would run a good ol 727 with a GV overdrive. Or the most "new trans tech" I would get is a 518 trans...lol
I like the 518, it is even simpler than GV and has a taller (more effective) OD ratio. It is just a 727 with a very simple and effective OD unit. Of course I like the a-500 even better because they are lighter, less drag, better 1st and 2nd ratios...
Very happy with a 518 behind my 5.7, runs great, put together a completely automatic controller for the OD/LU.
Had a RMVB with my old 340, that got old after awhile.
