I have a 71 Challenger that has a bad lifter and instead of changing just the one, I wanted to change the cam anyways so it's a perfect time. I was thinking of the Whiplash cam by Hughes but I haven't changed a cam in alot of years. Is there a video or website that I can see to get reminded how to do this?

check youtube. It'll probably be with the engine out on a stand and most likely a GM small block but its all the same principals.

I've changed a cam in my demon twice with the engine still in it, not too hard, just had to remove the radiator and raise the engine a bit for the cam to come out fully.

i just changed one in a 1968 dodge coronet, the radiator out and took the grill out, was a breeze

The last 2 times I did my 440, I pulled the rad with no issues. I even left the intake on, and used one of those tools to pull the lifters out.

Easy.