From your original post, to me if your headers went cherry red in seconds it says that your timing was severely retarded, pushing unburned fuel into the exhaust which was lighting off just outside of the heads. I'd be more tempted to run the cam straight up, and then ensure that the ignition timing is set to be "all in" at around 3000rpm, and somewhere in the 10-12BTDC at idle. Are you 100% confident in your timing mark on the balancer being dead on TDC? Also, you don't say what your distributor is, other than that you're running an MSD unit. It sounds to me like by retarding your cam 4 degrees you've hosed your performance, and I doubt that you're really getting 700hp but that's just a gut feeling.

Just my $0.02, and welcome to the forum, BTW.