Misfiring issue

Howdy guys, I have a bit of a puzzler. I decided way late in the season to get my long sitting Barracuda going. I put together a mild 383 for it, the engine is: 9.9:1 actual compression, ported closed chamber heads, Performer RPM intake, 750 DP Holley with Proform main body, (supposed to bump it to 780 cfm). 2" TTI headers, Mopar Performance ignition, chrome box, MSD Blaster 2 coil. Timing @ 36°, and it does NOT over advance.

I could only make 3 passes on the LAST weekend of the season, and my best was a 12.8, 102 and change. The car starts skipping at about 5,000 rpms, and I'm limping after about 1/2 track. The cam is the larger Summit grind, .465/.488 lift, 224/234° @ .050, and was degreed. I know the cam is small, but the Mopar Muscle article they did on the stock 383 showed the even smaller factory cam as making peak HP at 5,400 rpms. Shift point, (500 over peak power would be near 6,000). I can't come close to that. I thought fuel pressure, but I checked today, a constant 8 psi. My next thoughts are, the jets I put in are 70 front, 80 rear. Could it be lean enough to kill off the top end? Thanks in advance.