whether or not the 5.7 was reverse engineered it's hard for anyone but the actual designers to say...

I think a lot of the way the 5.7 diesel engine is, is to ensure compatibility with existing GM platforms and trans and utilize common exterior accessories. Or at the least to have the mountings standardized. Things like motor mount position and bolt patterns, bell housings, alternator & AC compressors, water pumps, etc, etc. Consider how many & how easily 5.7 diesel platforms were converted to gas engines.

The most rational & believeble explaination I've heard about the 5.7 was that the early years used head bolts that could not stand the compression of a diesel motor. It's likely that the 5.7 diesel used the same head bolts as the 5.7 gasser. The 5.7 has a reputation for blown head gaskets and cracked heads. Certainly indicative of weak head bolts. Expensive to repair and often terminal to any motor.

GM fixed this problem but the public image was already set. Kinda like the Fiero...early problems easily fixed but it still doomed an otherwise very good car.

I'd have to give the late 5.7 a thumbs up. And the early 5.7 a so-so, depending on a through inspection.

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1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5