The Whiplash cam is, in my opinion, a gimmick cam. It's designed to run pretty well but its main attraction is the choppy idle. Some guys just have to have the "sound".

The most important single point about a cam is the closing of the intake valve. Advancing the cam closes the intake valve sooner. Running a tight lobe center does the same thing. But, remember that the exhaust valve opens first, followed by the intake valve. Overlap is the time when both valves are open. Increasing the overlap makes that choppy idle sound. So to get a decent idle but still close the intake valve at the right time is a balancing act.
Now on to your cam needs. I'd suggest a camshaft with no more than 220 degrees @ 50 lift for the intake and 226 @50 lift on the exhaust. I'd pick an LSA of around 110 degrees and run the cam 4 degrees advanced. I think Hughes will have a cam for you as will Lunati and Comp. I am trying not to overcam the 400 because it is basically a big 383 and is easy to overcam.

If you are choosing between two cams, pick the smaller one.

R.