What is a good way to test a steering box

[Mustang_man298]

I just got the engine & trans out of the 82 today, I am told the steering boxes are difficult to change with the engine in, I was wondering if theres a reliable way to check it without driving it. The car came to me with a bad trans, so I have never been able to test drive it for play. My 80 seemed ok in the shop wiggling things, but gets loose feeling around 65-70 on the freway, very hard to keep in a lane on a windy day. I don't want to have a repeat of this again. The car has over 300K on the broken clock, unsure if it's the origional box or not, but suspect it is as everything else is still origional.