GM HEI ignition: Impressive and under-rated
 

I've spent some time recently chasing an idle misfire on one of my Innovation 600's. The top end performance was fine, but the engine was popping on a couple of cylinders at idle. I changed the plugs last fall and that helped, but it started doing it again the other day. The plugs looked good, so I pulled the distributor cap and found this. God knows how long I've been running without the center plunger button in the distributor cap - there was no sign of it or the spring inside the distributor, and there is no mark in the middle of the contact strip in the rotor. That spark had to be jumping a hell of a gap!

(TWO) new caps and rotor sets on the way: $56 including shipping from Taylor. Jegs wanted about $66...

Yup, have used them on supercharged 500+cid engines....carb applications too !

The center button is the typical electrical wear point.

I've never used Taylor cap/rotor (so i can't comment if good or not) just the typical AC Delco original equipment series and Accel on these EST/Voyager ignitions.

A few companies offer a better cap than the gm cap. Ive used the accel cap, better quality injected molded cap.
The draw back with a stock hei is how high they wiĺl rev and not spark scatter. Dui dist makes a modded version that will handle more rpm but if youre spending that much spend a little more and get a billet msd dist. Just my .02
I think above 5500 rpm is where the gm oem hei starts needing help. Rm

Btw a msd blaster coil will throw a 1" spark so you can open up the spark plug gap... and while your at it index your spark plugs... every little bit helps