You need to change the shaft to do it correctly, the manual steering shaft is longer and the coupler is different. It's really not really that hard to do.
I have one if you get stuck and are willing to wait a couple of months for it.
I have a steering box too.
P.M. me if you are interested.
I have several parts cars at my acreage in Cranbrook, B.C., so the shipping would be reasonable via Greyhound. I only get back there every couple of months or so.
Do you have a slant 6 or a V8?