Brady-
Sounds like the correct height and width. Be sure the bottom front-to-back dimension of the radiator matches the depth of those u-shaped brackets WITH the rubber cushions in place in the brackets (that's the 2-inch dimension of the radiator in the link; a 2- or 3-core radiator might be different thickness). You should also have a c-shaped bracket for the radiator top that mounts with 2 bolts where the hood latch is - this fits over the top tank at the center of the radiator.
I spent last weekend finding parts for my 66 radiator. You might also check out
www.completeradiators.com
They're usually on Ebay with the right new radiator for the truck for $157 plus shipping.