67 Dart 270...Project Old School
Just a thought...
I had issues with my dart at the track doing the same thing you described with yours (falling off at 4500-5000), it ended up being the mopar ign box was bad, and wasnt producing enough spark at the top end. I upgraded to a nicer mopar box and problem solved. I know that is the least of your concerns now... Keep up the good work on that motor...
JOE