chevy style HEI on 318

I am no fan of E-core coils on non-CDI systems.They are built for 500 or more volts input and because of that, don't seem to do well on just 7 or 8
The first question is what do you want to upgrade from, and the second is like it; why.
But if your engine actually needs something hotter, I highly recommend the Accell SuperCoil sq top P4120889 and it's associated 1.0ohm resistor P5206436, in my catalog. Put it on a relay, and I think you could weld with that thing. Mine has been absolutely trouble-free since ~2002; from 650 idle to 7200redline. I put mine up on the apron, horizontally, connections down, with a 30" hi-tension lead. Watch out! it does get hot.
I use the factory trigger in a 1973 distributor, that is on it's third or fourth engine. The trigger was replaced in about 2004, with another used one. The amp I use is built in to a Jacobs; dash-mounted,dial-back, electronic, timing delay box; that I installed in about 2004. The box also has a dial-type adjustable rev limiter.It works great as a cruise control; If I get to speeding, it starts messing with the sparks and wakes me up; very handy on long trips. Yes I really drive my 400+ hp 367/68 Barracuda on cross-country trips. She gets around.