Just to add to the post above, if you want a modern automatic overdrive but are put off by electronics, there are good options out there.
Chevy: Less than 400 HP, the 2004R can be used with a 2 wire hook up, no computer. A 700R4 can also be used with a simple stand alone unit with a 2 wire hook up or no electronics at all with a couple of internal modifications.
Mopar: SB LA engines can use an A 500 or A 518 from the early 90's with a 2 or 3 wire hook up to engage OD and TC lock-up (if equipped), no ECU. For early A, Poly and Hemi engines only the A 518 can be used with appropriate adapters, again no ECU.
B and RB transmission choices are more limited. I THINK there is an adapter to a LA bell housing allowing an A 518.
Options are endless....