What diesel engine would have come stock in the 1978 3/4 ton chevy and are those the ones with all the problems. I found one for sale thats in great shape for $800. 2 wheel drive, regular cab short bed 400 trans. any info would be great. thanks

I think they came with the P.O.S. 350 converted diesel, and yes those are the ones that had all the problems.

You don't drive it fast then it may last a long time. High speed meant failure for those engines. High RPM's is not good for any diesel engine.

its not a converted gas engine, can you convert it to gas, yes. but it was designed to be a diesel, case and point. they had problems, but they can be done to be dependable. just keep in mind that the 6.2's block was built a whole lot tougher when it come's to the bottom end. sometimes not tough enough mind you, but still more stought.

No doubt the ol 5.7 has a long list of weaknesses, not much power, not generally very reliable. Bout the only good thing is that if you find parts you can probably trade a 6er for them, everyone I know who has parts for them will be glad to give them away.

The 5.7 Diesel was never installed in a 3/4 Ton from the factory. Half-ton light duty models only. This was an interem fuel economy engine, not an HD truck engine. It was used to increase CAFE ratings so GM could continue to sell trucks without paying stiff fines to the EPA for every vehicle they sold that didn't meet CAFE. It served it's purpose in that respect.

The THM400 was the standard with the 5.7D. Most of them that my dealership sold were ordered with the optional 3.41 axle ratio to make them a little quicker on acceleration. Unfortunately, the lower axle ratio led to increased engine speed. Hence, increased engine wear and problems.

Everyone that had crank problems usually drove them at 85 MPH. The crank just would not hold up at high speeds!!!!

Ya, that B.S. the factory gave us about "Cranks coming out of the Canadian foundry were weak" was just that, "B.S." All the cranks came out of the same foundry. Many worked just fine and are still working today in both of my 5.7's.

The '78 has 200,000+ on it and the '80 has 246,000 and still eating head gaskets every 60 thou, even with decked block, heads and ARP studs. Guess it's time for solid copper gaskets and having the block O-ringed, huh? But...But...The fuel economy is worth all that work, dear, honest....