If you have a manual transmission, the original clutch equalizer bar won't fit. If you have an automatic, you will have to do some modification on the shift linkage.
I have one in a '56, with '57 and later exhaust manifolds. There was a clearance issue between the left manifold and the steering box, shimming the box at the lower boss helped, but I wasn't satisfied. I ended up swapping the left manifold for one from a '57 T-bird. The outlet is farther back and gave me good clearance around the p/s box. However, I had to modify the floor pan because the longer manifold hit it.
If I had to do it again, I would use my original box and use an electric assist on the column