HEI conversion problem - any input?

OK here's my application...

1967 273
2 barrel
mostly stock
was points ignition

Here's the problem...

Starts great.
Idles great.
Rev the engine and it flat lines around 1500 - 2000 RPM.
When I have my dial back timing light hooked to the #1 wire or any other and the engine is running, I get the steady flash at idle.
Run the RPM's up and the car won't rev above the 2000 ish mark and the light stops. No flash.

I've read and re-read other posts and I know I'm missing something simple.
I pieced my ignition together on Rock Auto
1974 318 distributor
New LX301 module
New e-core type coil ( 1988 Blazer 350 ci Chevy PN C611)
Relay sending a new power supply to module and coil ( double checked voltage to both )
Also checked and double checked ground/s.
I did need to "swap" my distributor wires the 1st time that go into module. It was a no start before that.
I also kept my set-up close and simple.
My relay is right next to my module, which is right on the firewall above the motor.
I do have that mounted on a 3/8" thick piece of aluminum for heat sink.
The coil is on a home made bracket right where the old coil was. So I don't have long stretches of wire. I also ran my distributor to module wires in a wire loom.

What if I had to "guess" is my hang up is my previous cheap copper core spark plug wires.
I have no problem in upgrading them, but want to get it right, so was thinking a spiral core.

So please hit me with any thoughts on what I missed, and thanks in advance.