After a lot of reading about ESD's, I thought it'd be interesting to ask Perplexity if I could add ESD to my 4.1/250 six cylinder Jimmy. This is the answer I got:
CAN I ADD ELECTRONIC SPARK DISTRIBUTION [ESD] TO MY 4.1 (250) IN-LINE SIX CYLINDER ENGINE:
The 4.1 GMC straight-six engine is a classic, carbureted engine. Many owners upgrade these engines with modern electronic systems-such as electronic fuel injection (EFI) or electronic ignition systems-to improve reliability, performance, and drivability.
There are documented projects where enthusiasts have successfully added electronic fuel injection and even turbocharging to similar GM inline-six engines, using aftermarket kits like Holley’s Sniper EFI, which is designed to be adaptable to older engines.
These systems often include electronic ignition control as part of the package.
Yes, you can convert a classic GMC 4.1 six-cylinder from points-based ignition to an electronic ignition system. There are several aftermarket kits available for this purpose, which improve spark reliability and reduce maintenance.
Yes, you can add EFI to your 4.1 engine. Aftermarket EFI systems, like the Holley Sniper mentioned in a similar GM inline-six project, are designed to retrofit classic engines and provide modern fuel and ignition management. This upgrade can improve starting, fuel efficiency, and performance.
SIDE NOTE 1: Back when my 69 step side, running a 250 in-line 6 was my daily driver, I went to capacitive discharge ignition. The points lasted so long, the rider rubbing on the distributor lobes wore down enough the point dwell started dropping off daily, from the 50 mile round trip to work. Loved that simple, cheap solution to 7 amps at the points frying them (the capacitive discharge dropped the amperage down to 200 milliamps (.2 amps), so the point contacts stayed in good shape for a long time.
If the capacitive discharge had failed, all I had to do was reach in, unplug the wire to the distributor, turn it 180, plug it back in to bypass the unit. Went from there to magnetic pick up and all was fine there too. Maybe. That is, it might have been performance could have been better.
I love hot rods, but think of them as like grandchildren and other small creatures of that nature - that they go home with someone else makes them even more enjoyable.
My thing was mileage. I had 6 forward gears, an RV cam, headers, fiddled with the 1 barrel carb, switched to radials. . .
One day, doing my best to go from Seattle to Bremerton at a steady speed, I pushed near the 25 mpg mark. Have to wonder what I would have got with: (1) EFI, ignoring the idiotic recommendation of 28 PSI for the tires, adding the air dam, switching to then non-existent synthetic oil, adding ESD would have got me.
SIDE NOTE 2: A 4:13 rear end still allowed me to carry and pull significant loads, and to pass comfortably, while still getting good mileage in 3rd over.