I have used whiplash cams with some real good results,and I agree its not quite right. I would avoid the MP 455 and the Voodoo suggested simply because they have a pretty wide lsa for what you have. Makes them idle smoother and have better vacuum but with the duration you will be running it wont be an issue.
The Comp is a little better,slightly narrower lsa for a similar duration but not so narrow that it will have a very rough idle and be hard to live with.
One other option is a Lunati Street Master 225/225 at .050 with 477 lift and a 108 lsa. I run one in my tow rig 440 and it helped it make some serious torque which is what you need with a heavy car and not much gear.
Keith