magnet vs led vs point trigger
I don't know about Jacobs, but I don't think that MSD currently offers a retro-fit that replaces points in YOUR Delco distributor (MSD does offer hot modules to fit factory HEI). I've heard many good things about the Pertronix points eliminator; most (Pertronix included) of the points eliminators are magnetic (Hall effect) "triggers"... but some (like the Mallory Unilite) use light/LED triggers ... the Unilites have a reputation for DOA failures ... something you can deal with at the track ... but not in a daily driver.
I don't know about the GM points eliminator ... it's probably a magnetic trigger. For a first-time ignition upgrade for MOST folk with a relatively stock-to-mild driver, I'd suggest simply replacing the points with a Pertronix or other magnetic trigger (GM too?) and replace-upgrade your factory canister-style coil with canister-style Pertronix or Accel Superstock or MSD Blaster or Mallory coils ... your GM dealer also offers both a GM-labeled MSD Blaster-upgrade canister-style coil and a GM-labeled MSD box. However, a decent factory point-triggered distributor is VERY, VERY reliable up to about 6K rpm (more if modified) ... and if it does fail ... you can troubleshoot @ roadside ... chevy points & condensor readily available ... most any bubba can R&R points.
I have also seen advertized at Mid America a stock-appearing hot HEI-type distributor that has a mechanical tach drive ... don't know who makes it and it's very pricey.
MOST MSD & Jacobs you hear about are add-ons (called ignition amplifiers) that change your factory "inductive" system to a hotter "capacitive discharge" system. Also, MOST MSD & Jacobs make a "multiple spark" that pulses plugs many times per event; these "spark boxes" usually require a fair amount of wiring and a PROPER place to put the "box" ... C3's are notoriously short of free firewall space. Typically, those boxes' harness carry a very high voltage also; instead of 12 volts at primary side of the coil (as now)... you'll have 400 - 500 volts there (careful with that inside cockpit, it can bite ... permanently!!!). And, it is not uncommon for a box to hum or buzz and produce heat. However, I understand that MSD has recently come out with a "Stacker" system (pn 7000) that virtually eliminates most additional wiring and has somewhat reduced footprint & height... but if you have points now, you'll still have points as a "trigger" with the stacker ... like other MSD boxes, the stacker does not eliminate points. MSD does offer a replacement-upgrade corvette distributor that has a magnet-trigger, mechanical tach drive and both vacuum & mechanical advance (pn 8572 about $290) ... however, it must be used in conjuction with one of their ignition amplifiers (spark boxes). A ton of street & bracket cars use the MSD 6 series CD boxes. Virtually all mid-to-upper NASCAR, SCCA and NHRA classes use a CD ignition ... MSD is by far the favorite and Jacobs is gaining a strong following ... Accel, Crane & Mallory have pretty good CD offerings/following too. Virtually all add-on CD ignitions require a spiral core-type spark plug wire set and probably a coil upgrade from stock too. I have two MSD boxes; a 6TN & 6M-2.
JACK:gap
