So theoretically, TBI ignition is an improvement upon HEI due to the computer modules that can adjust the ignition timing based upon the added sensors to the engine?
That's a tough question, but I would argue a narrow yes for the simple reason that there are fewer moving parts therefore easier to diagnose and repair, and it's more electronically oriented while still being pretty simple so an ECM pinout diagram and a noid light are at most the extra tools you'd need in addition to what you'd already have for HEI diagnostics (at least a multimeter, spark tester, and timing light), and those two extra things are exclusively to get readings related to the ignition control module. The ESC, TBI, and Vortec distributors are simply rotating assemblies so no issues with plates, weights, springs, or the vacuum canister. I would also say that the post-HEI distributors improved in accuracy because of the knock sensor circuit. The 'no' argument could easily hold water from a perspective of mechanical preference. A lot of people like to do a back to the basics build at some point and HEI is perfect for that because delivers spark in a modern fashion with only centrifugal force and vacuum changes dictating it. There's nothing electronic making incremental suggestions or affecting the whole advance curve. From the perspectives of voltage, efficiency, and longevity, I'd say they're all even up until the end of the Vortec incarnation.
Not bashing on HEI at all. It's a really good system that makes point breaker ignition look like Flintstones technology. In my opinion, point breaker ignition only wins in the sense that you can adjust it, and keep it going where HEI either works or it doesn't. I think incorporating some technology into these things and others was a good move, but there's a such thing as too much. Optispark on the Gen II motors sucks big time. It has an indirect mechanical input by optically sensing camshaft position and timing the spark based on that info, and it was totally unreliable in the long run. I don't like the Gen III coil-near-plug system, either. Not because it's unreliable, but because it takes eight coils, multiple sensors, and a complex PCM to do the job that one coil and a simple ECM/knock sensor (at most) can do. I know the second part is my opinion, but I'd say the top part is pretty objective. There are pros and cons, but the TBI distributor does win in terms of simplicity, granted that its simplicity comes at the price of electronic input, and accuracy.
