I'm not aware of any replacement R&P units that incorporate electric assist. I do know of a couple of add-on systems that utilize the existing rack. They fit between the rack and the steering column and shafts and proved EPAS.
Flaming River Microsteer Electric Power Assisted Steering system
https://www.flamingriver.com/fr40200...power-steering
Unisteer Improved Electra-Steer Kit
https://www.unisteer.com/collections...30004216889443
Here's a Unisteer installation in a FFR '33 Hot Rod:
https://thefactoryfiveforum.com/show...r-ElectraSteer
Note: Flaming River uses standard 11/16" x 36 spline connections, while Unisteer indicates theirs are proprietary (17mm x 36 spline) - but they do offer U-joints and connectors to match.
Another solution is an electric power steering pump with a hydraulic PS R&P. This video uses a Volvo PS pump:
https://www.youtube.com/watch?v=Htrz_Wn4SZ8
This video also mentions Toyota MR2 end Mazda 3 electric PS pumps.
Here's a write-up on installation of this in a Fox body Mustang:
https://www.corral.net/threads/volvo...te-up.2499503/
Electric power steering will draw quite a bit of power, so make sure your alternator and electrical system are up to the task.