It was a few year ago, but I don't remember having any trouble just taking it out and putting the new one in. The 67 service manual has instructions on how to take it out, although the 68 manual doesn't. Mines a 68. The manual says to loosen the fender bolts at the firewall, I didn't I left everything on the fender mounted tight, I didn't want anything to shift as I didn't want to realign it all. I got my replacement from Ames. Was the correct shape, nice core only problem I remember is one bolt hole for mounting the rad may have been missing or drilled in the wrong spot. But then my rad is not stock so in may have been the rad not the support.

One thing it did lead to, was all that ugly wiring hanging down got me to rip it all out and make a custom harness. My car is not stock, wouldn't have done that if I was doing a restoration.