Why do people have to pass away before the story can be told?
Correction: Others did not offer low compression. GM, Ford, and others had a
high compression IDI engines ~21:1 just so they would get enough heat in the massive cold prechambers with the low pressure injection systems of the day to actually start. The DI 5.9L Cummins was 17:1. Dodge RAM didn't offer a diesel for most of the 1980's and IMO missed out by not offering the 5.9L in the Wagoneer. Maybe they missed out on the pain: tech training, clueless public about diesels, dirty wet diesel fuel...
You are worried about rumors so consider this: "Gasoline engine conversion" is incorrect old rumor for the 350 (5.7L) Olds 22:1 NA IDI
Diesel Hand Grenade that ruined the NA diesel market for over 20 years.
That Olds Diesel put Lemon Laws on the books while other engine and vehicle "bean counter" disasters say like the Chevy Vega oil burner or the Ford Pinto cremation coffin on wheels couldn't. (There was a low boost, ~3PSI, turbo kit offered for the 5.7L Olds as one barn find El Camino with one sold on ebay years ago.) As an aside it wasn't a new thing to do as many gasoline engines were successfully converted to diesel. Regardless The Olds 5.7L Diesel had a different block casting with thicker cylinder walls with a injection pump mounting casting in the valley, different pistons, etc, but, used
the same assembly line tooling as the gasoline engine to save tooling costs. New at the time, with ZERO dealer tech training, single use TTY head bolts were used to try and overcome the lack of head bolts needed to hold 22:1 compression with diesel combustion. Same dimensions as the gasoline engine so the same tools could machine the diesel 350 block... Same tools caused the lack of head bolts. And thus the conversion rumor was born. This 350 (5.7L) Olds Diesel hand grenade was offered in pickups before the 1982 NA IDI 6.2L was offered.
Other diesel engine were proposed before the 5.7L disaster but the Cheap Cheap Cheap at GM couldn't turn down the tooling cost savings and bypassed the R&D. Others argue the cylinder deactivation Cadillac engines of the era were worse, but, clearly didn't have the widespread impact the Olds Diesel disaster did.
Oddly the IDI 6.2L Diesel is still in production as a punched out to 6.5L because the military needs them and treats them as the disposable and expendable engine they are.
The above context, GM's Diesel Bean Counter Diesel Disaster while GM's arrogant board of directors worried about their stock payout vs. EDS Ross Perot's is why it took a HD diesel engine to put Dodge RAM pickups on the map. Detroit Diesel, that GM owned, said use a Forged Crankshaft in the 6.2L diesel that came out in 1982. GM didn't and "Like a SNAP!" it later took a 100K warranty to sell the IDI 6.5TD diesel to the public.
Suppose the above is why they figured in the day: Maybe we sell only 1000 Dodge Cummins pickups.
Getting a gasoline engine to start and run without say vapor lock with high aromatics on unleaded of the early 1980's and the Big 3's arrogance to not bother with a better design like sublet fuel injection is in-line with the mediocre diesel offerings of the day. Of note Oldsmobile gasoline engine camshaft failures... The 1980's is why there is no longer a common "Big 3" in everyone's driveway like there used to be.
If this Cummins project didn't happen we would be talking about other legends like Ford's IDI or the Mercedes IDI that offered a optional turbo from 1979 on.
Because the Cummins project happened GM had to eat crow and work with Isuzu to build the Duramax. Then GM continued to insult diesel owners everywhere with "disposable diesel" engineers that have no business being anywhere near a "reliable" diesel engine.
FWIW Pictures say what's up better. 2003 5.9 HO Cummins vs. 1985 IDI 6.2L GM. Both engines failed. The 6.2 was scrap metal with cracks everywhere and a trashed
roller cam. The Cummins had already been sleeved likely from a valve seat failure but was a failed rebuild as the sleeve was moving.