OK, I had a transmission shop, run by a friend (now out of business), "build" me a 700R4 trans. I've installed it in my '70 Nova, behind a "new" 355 sbc engine. I've done the preliminary TV cable adjustment per You Tube videos, and tech articles.

Now, I hear about "electronics".
I have read that the 700 R4 is not an "electronics" transmission! Just adjust the TV cable and go.
Yet, another trans shop owner tells me you need to hook up the "electronics" or burn up the trans when driving at sustained highway speeds!
I wish I'd just installed a TH400, per my original plan.
Someone please clear up this quandary for me... do I need "electronics" or not?
Thanks...

 

The lock up clutch in the torque converter is controlled electrically. This will comprise of a brake pedal switch, vacuum switch, pressure switch or two in the valve body and a solenoid in the trans. Summit Racing sell a kit for this.
https://www.summitracing.com/parts/tci-376600/overview/

 

I used to rewire the factory pressure switch connected to the valve body.
Make it so you apply key on power to one side to of the switch, when it goes into fourth it locks up a few seconds later.

I would always break the key on power with a three position toggle switch, one position would be off, one would be on, one would be automatic through the pressure switch.

Never needed a brake switch, people swear you do but I guess they never drove one like this. It unlocks on the 4-3 downshift, which happens pretty quick when you stop fast.

 

You kind of have to know how they set up the trans inside, as far as lockup.
Some use a pressure switch for 4th gear lockup, which is what I have, just use a toggle sw for lockup.