Technical Power Steering Into a 39 Pontiac. What gearbox?

I think the offset from the input shaft, to the mounting lugs, is the same. The main body extends to the side, past the mounting lugs, a ways...usually the frame is relieved here, you could do the same by cutting out part of the frame and welding in a curved section for clearance.

 

I like your thinking agele55 could use his stock box and pitman arm, but would he need to modify the column?

 

Damn... I guess I got locked in the "old school" room without a key. Didn't even know there was such a thing.. I will Google this concept also.

 

What about a S10 pickup box? I don't know the series on them, but that is what I used on my 47 Lincoln. Had to open up the tie rod hole just a bit to fit my stock tie rod end.

 

Yes. Cut the stock steering shaft and connect to the EPS with a U-joint.

Yep, the yards are full of 'em. Under $200 start to finish. There's a couple of different ways to do it. This is the way I installed it in my '54 Ford Customline...……….
https://www.jalopyjournal.com/forum/threads/epas-install.1193648/

 

That's a bit of an oversimplification...........

 

Have you tried a parts store? I went online to one I used to work for and found several boxes with a 1.25" output spline.

https://www.oreillyauto.com/shop/b/...?q=steering+gear+box&prodAttr_31408=1.25+Inch

 

These are listed for a 78 Pontiac Firebird.

https://www.oreillyauto.com/shop/b/...3ea/1978/pontiac/firebird?q=steering+gear+box

 

I posted this on another steering box thread. maybe it will be useful here.