I have the 3.0 engine about ready to go into the SD. Note that this is a .961 block. The .960 block might have other differences. Here are the differences noted thus far:

Oil filter housing = the top oil cooler line is parallel to the bottom cooler line in the .971 housing. The cooler lines are rigid where they attach to the housing so forcing 140 lines into the .961 housing might be difficult. Also the housing mating surfaces are the same but the passages in the block look different. There's something in the FSM about a redesign. I'm not going to worry about it unless the oil pressure gauge suggests there's a problem. EPC shows the same gasket for both engines.

AC bracket = the .971 AC bracket has a more spread bolt pattern for the compressor. I suppose that means the compressors are different. Well they must be if one was designed for R12 and the other for R134a but I guess the casings are different as well.

Alternator bracket = the .961 alternator bracket mounts with 5 bolts while the .971 alternator bracket mounts with 4 bolts. There is no 5th boss although you can seemingly use either bracket in either block. The turbo isn't on yet so I don't know if there are clearance issues or if the .961 relies on the bracket as part of the turbo lower support. The .971 turbo rests on a strut that bolts to the engine mount arm.

Turbo drain = the fitting on the block that receives the turbo drain tube is about a half inch taller and is aimed more vertically.

Engine mount arms = way different but attach at the same points on the block.

Front cover = 1/2" or 13mm freeze plug in the dipstick location but it looks like a .961 dipstick will work. I don't know if if a front dipstick will work with a .971 pan. As it is my SD came with a 104 pan!

Turbo = turbo oil supply fitting on the block is the same. I don't know if both engines use the same line. Turbo placement might be different because of the Euro exhaust manifold. Compressor housing and wastegate housing are different. The .961 turbo is longer as a result. Either wastegate housing bolts up to either center section. The .971 uses a bigger compressor wheel which must be used with the .971 compressor housing. You can keep the .96 turbo if you swap in the .971 wastegate housing and trim the turbo air intake hose by a couple of cm (there's another post on the differences). The mixing pipes are different. The .961 EGR comes into the pipe from the front, the .971 EGR comes into the pipe from behind. The crossover pipe looks to be the same.

IP fittings and attachments are the same. I don't know if the sensors and actuators are the same but the connectors look familiar.

Radiator hose fittings look to be the same. Cabin heater supply line is different between 126 and 140 but either line plugs into the same fitting on the back of the water pump housing. There is a plug in place of the temp sensor beside the thermostat.

Bosses for oil cooler line clamps look to be the same.

I'll lay the .961 oil pan in the 140 engine bay when the 3.5 comes out to see if the side extension will cause problems.

Lots of little things (and big things) different in the head but chances are you can keep what you have from the 140.

Remaining big questions = will the flywheel, driveplate and transmission bolt-up???

Sixto
93 300SD

Oil pump = I haven't gotten to choosing an oil pump. On one hand I'd like to keep the .961 oil pump with the .961 oil filter housing but there's the matter of the 104 oil pan. If the pumps are externally identical I'll probably opt for the .961 pump.

I don't know if the 104 pan has the same baffles as a .971 pan.

Sixto
93 300SD

Yet another difference. The .971 oil pan has a boss at the front left corner for a clamp to support the engine oil cooler lines as they bend to the oil cooler. The .961 pan doesn't have a boss in this location.

Sixto
93 300SD

Upper hose fitting = The upper hose fitting of the .971 has a nipple for a hose to the reservoir. There's no return hose from the radiator to the reservoir.

Sixto
93 300SD