Diesel recommendations

[Grande Bob]

Picked up an 80 Sierra that originally had a 5.7 diesel but was swapped to 350 olds. I’d like to bring it back to diesel just wondering if anyone here had a suggestion for a great little diesel to make the old girl feel like herself again

 

[Strick]

The 82 up Detroit 6.2/6.5 are a good engines for what they are. I am fixing an 82 K1500 6.2 as we speak. I have seen where many folks have put Isuzu 4 cylinder and Cummins 6 cylinder engines in Squares as well. I would love to do a DMAX swap on one but the width of the Square frame and the width of the Detroit DMAX is not very accepting.
Also, you may need to change the transmission if it does not have the multi-use bellhousing. It should have a BOP (Buick/Olds/Pontiac) if it has an Olds rocket installed.

Strickland

 

[Blue Ox]

If you want it to feel like it did when it was new put a Kubota in it.

A 6.2/6.5 is an easier swap, but that transmission issue that Strick mentioned, and it's just not a powerhouse. so if you're content to have a diesel that drives okay and sounds good. That would be the recommended path.

Other than that, a 4cyl Cummins B performs about like a 6.2L, probably weighs more, and will be noisy and vibrate. However if you can find one out of a "bread truck" it should have a GM automatic attached to it.

Otherwise, the Isuzu suggestion isn't bad. Those little fours that were in the cabover trucks would probably be a good choice. Although I'd definitely take a tape measure to it before you invest.