95 od trans to 1973 la motor

You'll need a 360 lock up converter and flex plate .

Yes you can use the lock up feature and O/D by adding 2 switches to power the lock up and o/d. You have to do this manually.

I think someone makes a control unit for this in the aftermarket that will do this automatically.

BTW you'll have to cut up the floor and fab a trans mount .

I'd go with a built 998 and GearVendors . No mount fab, just some metal massaging for the GV.