Well, I know that when I want to increase, or decrease my compression ratio, on my small block Chevy, I can use a thicker, or thinner head gasket. In jumping down from an .077 thick gasket, to a .027 thick gasket, I can change the compression from 9.5:1 to 10.75:1. That's a pretty big difference, and changes the whole attitude, and output of the motor. This alone with no other mods, gains me a significant amount of horses, and torque. Not sure if these exact same principals apply to diesels, but I would think they would. Why would they not?
I bet if I did this with my 79 300cd, non turbo cars, they'd have an easier time with winter starts, etc. Just a theory though.

If anything, I'd want a thicker headgasket to lower my compression so I can run more boost.

Right, me too...But no boost factor to consider on a non turbo car, right?

Older cat's (1950-1960's) usually had pony engines that always started, if you could get the pony started...

In the army, lots of mechanics paid for multifuel engines when they used smelling salt (ether) on manifold heater engines...As an investigating officer, I cited quite a few idiiots in Korea in the winter...

so it goes...

__________________
71 220D 169K wrecked
83 240D 118K sweet 4 speed
91 350SDL (one of the 60% good engines) 156K
84 300d (loaner to my sister) 189K
79 300SD (partswagen)
86 420SEL partswagen
70 220d (partswagen)
68 280s GASSER!!! under construction now
85 300sd 310K miles winter beater car retired
93 300d 2.5 turbo 168K wife's car
83 280SL euro 5 speed 155K
69 250S newest project 54K

OH boy.
Well I can clear up all of this Olds 350 Diesel stuff. I've owned both gas and diesel versions, and still own my 83 Olds Custom Cruiser Wagon, diesel car.

The Olds diesel is simply a four bolt version of the traditional two bolt Olds 350 gasser, with a different set of heads, forged crank, rods, and pistons.
As for the fuel injection mount, it just bolts to an adapter attached to the front of the block, and robbing power via a gear-set from the cam gear/timing set. When the fuel injector pumps would seize, they would take out everything related, or effected by the cam.timing set. They were junk though. They were not related at all to the Chev. The 4.3 Olds diesel was nothing more than a buick 3.8 v6 w/different crank, pistons, and heads etc. to bring it up to 4.3 litres.
I still love the Olds 350 diesel though. The original engine in my wagon lasted an astounding 409,000 miles by some stupid fluke. The engine was replaced last year by the G.M. dealer for a brand new retrofitted crate engine. It was still covered under G.M.'s recall, because they set the cars up with a lifetime recall issue on them. They didn't expect my car to roll into the dealership for a new powerplant a whole 24 years later I bet.
The Olds 350 Diesel engines were very saught after by racers, only because the block was four bolt main. They were very easily converted to gas jobs. At one time, back in their day when they recalled and fixed these cars at the dealerships, they would do the actual conversion to the engine while in the car, to make them gassers. All they did was pull the heads, intake, injector pump, and an assortment of other components like the pistions, and cam etc. and swap in all gasser parts into them w/o ever even pulling the engine from the car, in some cases. They'd just take it apart for an "In-frame" as a diesel, and put it back together as a gas job. Same block, and even same crank and rods. Now, these gasser cars, had an Olds 350 four bolt main, gas engine, w/forged crank,rods, pistons, and a host of other goodies. We all know this is the best type of set-up for a stout cam, and a great musclecar engine. All the racers used to look for the diesels, or former diesels to put into their 442's and other Olds race/street cars. Makes a lot of sense actually. That was the only 4 bolt block Olds ever made. Dispite all rumors though, the block was not cast out of any different materials than the gasser 350's were. No Nickel jsut normal formula. I do not know the exact compression ratio of the Diesel version, but fom what I've gathered from the Olds Diesel web site, it was in the neighborhood of 21:1.