popping at high rpm

Hi all, I've been building a 340 scamp for the track and I finally got it out on the track a couple of weeks ago and i went through some I guess you'd call them bugs that had to be worked out. One was that the motor was missing on the top end, well i jetted it up and that took care of the missing issue. I then had the issue of running out of motor in the last 400 ft or so. I found out that the distributor clamp was loose and the timing had changed dramaticly, i got that fixed at home. I then took the car to the track yesterday and with the proper timing in it at 14 initial, 20 mechanical, 34 total. The first pass was good but still a little short on motor at the top end so i jetted up to 73 primary and 83 secondary and i picked up another 2 tenths. Keeping this in mind i'm shifting at 5400 with no miss whatsoever. Well on the next run, at the burnout I mistakenly didn't get the tranny back in first, so I left the line in first gear and it shifted into second way to soon. Well I reacted by shifting back into 1st instead of just writing off the pass, well when I did this it reved what had to have been around 7000. Right after this the motor developed a miss/pop/backfire around the 4800-5000 range. I backed off the timing and it was still there. I removed the valve cover and did a quick visual and found no obvious signs of damage. While sitting there and just running the motor up i can go to 7000 without a miss. I checked the coil and it was hot, but no hot enough to where you couldn't grab it and hold on. All electrical connections were tight, checked the cap/rotor and there seemed to be no issue there either. I can't see the fuel pressure due to the guage is under the hood.

My thoughts are either the fuel pump got hurt, (it's a manual pumper 80 gph I believe) or the elec box is done.

now here's what I have in the motor and electronics

340- stock bottom end, 10.1 comp,
mildly polished and ported j heads, gasket matched intake and exhaust.
stock rocker assembly
comp springs, retainers and keepers to go with cam
competion cam single pattern 484 lift [email protected] if i'm not mistaken
RPM air gap
old 750 holley, (doesn't even have power valve protection) but was cleaned and professional checked out
FBO recurved distributor, coil and box
904 trans with stage three manual shift kit

I'm going to pull the rocker assembly off and check push rods and make sure no springs are broke

Can ya'll please direct me in the right repair direction

thank you in advance

Kevin.

PS. IF i've missed any info that would help, please ask and i'll fill in the blanks.