Vannin' Home Forums Chevy How to.... replacing gas 350 with diesel 350

Are the diesel 350 small block and the gas 350 the same motor mounts tranny bolt patterns etc? Can I replace a gas motor with a diesel?

Diesel cost more than gas here ...

Yeah but better mpg with diesel and very hard to find a replacement motor here in Ireland.

Hey Shaggy,

I think, yes, being a Chevy, Not entirely sure, but If they bolt it up to a T350/400 at the factory, It stands to reason it would bolt up.

FYI A major shortage of diesel coming in June. Inventory is beyond low now. From the article posted on Twitter:

We are looking at a nightmare in terms of global diesel shortage that will shock people starting June.

Diesel inventory on the east coast is 18 million (About 3 days demand) as of today, we will run down to sub 10 million. 🚨

This is WAY below historic inventory levels

https://twitter.com/WallStreetSilv/status/1523329724792991747?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1523329724792991747%7Ctwgr%5E%7Ctwcon%5Es1_&ref_url=https%3A%2F%2Fwww.riverdavesplace.com%2Fforums%2Fthreads%2Ffuel-prices-corporate-greed.251985%2F

I did the math on this once. The diesel will cost more to operate than any fuel savings will create. I did it based on running a 6.2L Suburban vs. a 350 gas Suburban like 15 years ago and at that time it was basically going to cost me the same to get 14 mpg out of the gasser as like 18 out of the diesel.

The 350 diesel is still another animal. It's based on an Oldsmobile block, so it needs a BOP trans with a diesel governor on it. They had issues with head bolts stretching. They have all the power of a 4.3L gas engine, although more torque, and if you think finding Chevy 350 parts is hard, this long hated motor they made for six years in the 1980s is going to be much worse.

I'm not even sure the mounts are in the same place, I saw plenty of formerly 350 diesel pickups with Oldsmobile and even Pontiac gas V8s stuffed in them. That tells me you have to move the mounts or get different ones for a Chevy engine. The 6.2 on the other hand should swap over more directly. But you'd almost need a parts truck to get the lift pump and filters and so forth that you need to make the swap work.

OK, I'm convinced.....

I'm gonna stick with gas, I've had a guy reply to a wanted ad I put up with a 350 SBC (gas) and torqueflite box.

I presume it's easy to switch the torqueflite for my TH350?
Thanks for your helpful replies guys.

Correct me if I am wrong, did you not just rebuild the motor? Is it giving you problems? Remember the parts you put in that engine are better than what gm had, you should get an easy 60k (miles) on it. Am I wrong that you have a rare 400?

Torqueflite isn't even a GM transmission, I don't know how they have that bolted up.

No don't have a 400, yes I did rebuild it BUT on the way to a show the alternator bracket came loose which meant the belt was loose and not driving the water pump and it boiled the oil and cooked the motor on a hill. Bearings are toast getting the crank checked out at the moment.