Top End Miss

Do your self a favor and junk that P.O.S. and buy a CHEVY,,problem solved !!

All kidding aside, I have read and re-read all posts and I gotta say it sounds like a fuel issue. Scamp made a valid point on reading the plugs.Old Harley guys used to jet by the plug readings ONLY.Make a pass(anywere safe) full throttle,when you hit high gear click off the key and drift to a stop pull the plugs and see what they look like.
Gears make it rev faster, sooner,SOOOO how about a fuel pressure reading at high RPM's?
Now this one is just for fun(food for thought)During a B.S. session talking to the guys at Indy Cylinder heads the jetting question came up"how much is enough?"Answer=" if your staging and your eyes ain't waterin' and you still can breath it ain't fat enough !!"
So you said jetting fat made it slow down and still popin,,, it may be fuel delivery as stated before. You runnin' a relay on that pump? Maybe you got a voltage drop.
You tested the ignition and wiring system so I really don't know what to say but anything electrical can die at any time new or not.
I know you can fix this, don't give up or I'll sick MadMax on your a$$.