No computer needed, but they do make a nice little shift command box for it that lets you set the shifts where you want them, but I think it's a little pricey.
That's here, and it's good for the A500 as well as the 518 since they are the same control wise.
COMPUSHIFT Mini for Chrysler A518/46RH and Chrysler A618/47RH
Myself I plumbed a steel line off the governor port and used adjustable pressure switches.
I have it set where OD comes on at about 50 and converter lockup around 70.
It's pretty easy to wire since all it needs to apply OD and lockup is 12v to either or both of the two trans terminals on the side of the trans so getting the plug with the trans is nice if it can be done.
This gives me 2,100 RPM's at 80 mph and right at 25mpg with a mild built 5.9 Magnum in the Dart with a 2.73 rear gear.
My car is a daily driver hiway car and not an in town racer, but the low ratio first gear of the A500 get's it off the line pretty quick anyway.
The speedo assembly off the 904 is perfect.
Current starter also works just fine.
You do have to egg one hole on the flex plate about 1/8 inch for the A500 converter, but other than that it all bolts right up.
And as mentioned already, all your existing linkage swaps over no problem.
