One of the major issues with the HEI system is the rotor, or, more precisely, the composition of the rotor. What kind of plastic/composite is used makes a huge difference. While the OE rotors will still have the same failure issue, the aftermarket replacement rotors are absolutely junk in comparison, with the exceptions of a couple of the High Performance ignition manufacturer's parts.
What happens is the electricity from the ignition system naturally wants to find the easiest way to ground....usually that ground is the side electrode of the sparkle plug. Once the plug electrodes wear, the gap widens, or there is an issue with the plug wires, the ignition voltage wants to find a quicker, easier path to ground. The closest ground there is is the two screws that hold the rotor to the distributor shaft.....and THAT'S where the little lightning bolts on the bottom of the rotor come from, and the blackened look of the center of the rotor. The ignition voltage is literally jumping thru the plastic of the rotor, going to ground. I've seen rotors that were so cheap they would melt a hole right thru the center in about a week of driving.
Anyway, the whole point of this is to use the best quality ignition components you can on an HEI system....it could mean the difference between getting home, or getting a tow twuck...
Also, if you happen to have a violent backfire thru the intake, that can blow vacuum lines off, as well as damage some of the gaskets in the intake tract...and if ya have a Holley sitting on top, you can bet yer booty it just blew the power valve all to smithereens....
______________
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"