Dany's Magnum swap is back!! with Ignition woes now..

Well the track finally opened here and we got a chance to test the new trans/converter.
But with the temp being so high that day, the 45 min trip on the interstate and the long line into the track and thru tech the car got pretty hot, 217 degrees !!
her first launch it started popping out the exhaust at about 3K like the ignition was breaking up.
Reminded me of how my old Shovelheads would do with a bad condenser.
We let it sit for an hour or more and Nick my youngest gave it a try and it did the same thing.

So I took it out on the main road to the track, and it drove completely normal unless you floored it until 3500/4000 RPM and then it began to miss.
Couldn't really hold it like that on a public street as long as on the track but I got the idea.

It sat overnight at the house and on the drive to the shop the next morning I was able to get on it on a straightaway and it pulled fine.
But by the time I reached the interstate the temp was 205 and I hit it pulling on and at the top of 2nd it started to miss a little.
So I'm thinking this is heat related breakdown of something in the ignition system.

It is as follows:
MP electronic conversion "Kit" NOS from the mid '80's.
Japanese orange box, Distributor and wiring harness. Been on the car maybe 3 years, less than 3K miles since it was installed on the original 273.
Original coil from the 273.

Standard Ign wires, unknown age, but OLD!!
The wire looms on the wires I made when I was 12 (I'm 54 now..lol) so we are going to start with wires/cap rotor.

This is a pretty tame combo and we are shifting at 5K RPM so I don't think we need a "Killer" ignition system, but if I'm gonna replace stuff...

So our questions are this, If the problem persists after the wires/cap where would you go next?
Coil?
Orange box?

I am intrigued by the FBO setup and have one of their limiters in the MP dist now.
But at $260 there goes the drag radials again!!
And I'm just not sure the combo needs it.

I can rob a "test" module and coil off the wifes duster as a test but wondered what the next step above what I have now is?

Pertronics Flamethrower coil?
Which one with the orange box?
Can I eliminate the ballast with an aftermarket coil, and will it be any help to do so?

If it ends up being the Orange box, does anyone make a decent replacement in our China incrusted age besides FBO?

Or is a GM HEI module conversion the way to go?

I think I have given myself TOO MANY OPTIONS!!

Here is the setup we copied:360 TrueStreet Magnum Build