64 Valiant power steering

So steering box 62 to 72

'62-'72 A- or B-body, right.

use my pitman arm from manual box

If it's good

I have a pump pully and brackets from 83 Dodge truck

Okeh

If I shorten the coloum will the 64 manual cuppler fit?

I'm a leetle grey on that answer. It might, I think it probably will, but in some years a different coupler is listed for power vs. nonpower steer so there may be a difference there. You may want to look at a Borgeson coupler (discussion here) for a probably-superior alternative to a factory-type coupler, but you can also get new factory-type couplers from Steer and Gear, see here. They say their couplers are for '66-'82, but every '65 I've seen and owned has used this kind of coupler, and it's easy to use this kind of coupler in a '62-'64 A-body.

Let us know how it goes!