Olds 350 vs Chevy 350?

[Coronettom]

Hello all,

I'm asking purely out of curiosity...lately on CL in the NC/VA area I've been seeing quite a few guys with Olds 350's in their trucks. I know literally nothing about Oldsmobile engines so what is the difference? I'm just wondering why someone would go with an Olds 350 when there seems to be no shortage of Chevy 350's out there? And with that said I have a lead on a 350 from a cutlass S, would any of you out there consider it? Just lookin for some more knowledge. Thanks everyone

Tom

[Indian113]

Performance parts for a SBC are plentiful and Cheap. Olds parts are a lot higher

[Clyde65]

A LOT higher!

I used to run a 68 Cutlass with a 455. It had torque to spare, could pull one front wheel completely off the ground at a stomp. I paid dearly for the performance parts for it, I also had to have some parts made because at the time they weren't available.
I would say BOP performance parts are 2-3x the Chevy parts cost. They are torque monsters though!

[geezer#99]

Originally Posted by Coronettom

Hello all,

I'm asking purely out of curiosity...lately on CL in the NC/VA area I've been seeing quite a few guys with Olds 350's in their trucks. I know literally nothing about Oldsmobile engines so what is the difference? I'm just wondering why someone would go with an Olds 350 when there seems to be no shortage of Chevy 350's out there? And with that said I have a lead on a 350 from a cutlass S, would any of you out there consider it? Just lookin for some more knowledge. Thanks everyone

Tom

Usually an olds motor replaces a diesel in a truck. Cheaper than replacing the diesel. And the olds bolts up to the tranny as the diesel block is based on an olds motor. Olds and chevy motors have different tranny to motor bolt patterns. You can buy adaptors to put an olds tranny to a chevy but that's more expense.
You can swap a complete olds motor/tranny into a chev though. Olds has different wiring requirements. Starter is on the opposite side.

[Coronettom]

Thanks for all the replies. I had done a quick search at parts and saw the prices were more expensive.

It makes sense about the diesel swap. come to think of it, growing up my dad had 70s-80s c20 with a 455 Olds in it. I never asked why but now I wonder if it's bc it was originally a diesel. Pretty interesting! Thanks again everyone, I'll pass on the Olds 350!

[Boog]

If you want to drop a stock 350 or 455 olds in the truck you won't be out a lot of extra money on it. And if I'm not mistaken the 455 drops in using bb chevy mounts. It won't be as cheap as a small block chevy for a small block chevy swap since stuff like exhaust and a different radiator may be necessary.
As said it's the performance parts that'll really cost you.
I dropped a 350 olds in my 56 ford pkup back in the early 70's. I loved it. With a 3.73 gear it was fun. A 455 would be just that much more fun. And not to mention olds engines aren't that much in demand these days one should be reasonable to buy.

[GASoline71]

The 350 Olds is physically bigger. It is the same size as a 455. The intake manifolds weigh dang near 100 pounds! Where as a Chevy 350 is way smaller in size than 454.

Gary

[truckster]

There are some advantages to the Olds 350. It has huge journals, meaning loads are distributed over a greater area. The bore is oversquare, meaning that it's going to rev well.

On the other hand, you can build a lot more Chevy 350 for the same amount of money. I love Olds motors, but I can only see myself building another one if I have a lot of money to spend and I'm bored.

[DieselSJ]

Originally Posted by geezer#99

Usually an olds motor replaces a diesel in a truck. Cheaper than replacing the diesel. And the olds bolts up to the tranny as the diesel block is based on an olds motor. Olds and chevy motors have different tranny to motor bolt patterns. You can buy adaptors to put an olds tranny to a chevy but that's more expense.
You can swap a complete olds motor/tranny into a chev though. Olds has different wiring requirements. Starter is on the opposite side.

LOL...the 6.2 that came in our trucks was NOT based on the Olds engine. The Olds 350 diesel was very loosely based on the Olds gas engine, and that diesel was NEVER installed into a Chevy or GM truck. The Olds will not bolt in place of where a 6.2 was installed. The 6.2 has the exact same bellhousing pattern and the motor mount locations as the SBC and BBC.

[GRX]

Olds 350 are decent. Ran them in my '69 Cutlass. As you probably already know. Easy ID is their oil filler tube at the timing chain area. Valve arrangement is different than the SBC too.

If you go with one stick to the earlier '68-'76 engines. Later ones were light castings with weak windowed main webs. About every one I saw with miles on them had main saddle alignment issues. 403 are just as bad.

Olds 455 were torque monsters. Big reason you see them in boats.

[clinebarger]

Originally Posted by DieselSJ

LOL...the 6.2 that came in our trucks was NOT based on the Olds engine. The Olds 350 diesel was very loosely based on the Olds gas engine, and that diesel was NEVER installed into a Chevy or GM truck. The Olds will not bolt in place of where a 6.2 was installed. The 6.2 has the exact same bellhousing pattern and the motor mount locations as the SBC and BBC.

The Old's 350 diesel was installed in some 1/2 ton trucks.

[Boog]

If memory serves me right the 350 olds diesel used a stock gas block with different heads. That being the reason they didn't hold up well. The auto makers were in a big hurry to get something on the market to get better mpg in the late 70's after the fuel shortage in previous years. They were installed in full size cars and 1/2 ton trucks. Class action lawsuits were filed against GM over these. It really hurt GM. Those were bad years.
That diesel was also installed in intermediate cars too as i had an 81 Cutlass broughm that had an olds gas engine replacing the blown diesel it came with. And that was the small Cutlass.

[Shady Rascal]

Originally Posted by DieselSJ

LOL...the 6.2 that came in our trucks was NOT based on the Olds engine. The Olds 350 diesel was very loosely based on the Olds gas engine, and that diesel was NEVER installed into a Chevy or GM truck. The Olds will not bolt in place of where a 6.2 was installed. The 6.2 has the exact same bellhousing pattern and the motor mount locations as the SBC and BBC.

You ever stop and think that there were diesel GM pickups before the 6.2 ? Plenty of them. Geezer#99 is absolutely correct.

[GRX]

Originally Posted by Boog

If memory serves me right the 350 olds diesel used a stock gas block with different heads. That being the reason they didn't hold up well. The auto makers were in a big hurry to get something on the market to get better mpg in the late 70's after the fuel shortage in previous years. They were installed in full size cars and 1/2 ton trucks. Class action lawsuits were filed against GM over these. It really hurt GM. Those were bad years.
That diesel was also installed in intermediate cars too as i had an 81 Cutlass broughm that had an olds gas engine replacing the blown diesel it came with. And that was the small Cutlass.

Main problem with Olds 350 diesel was blown gaskets & heads cracking. About every single one I put on the magnaflux machine was that way.

The 350 diesel blocks were not same as their gas brethren. Thicker casting designated with a big 'D' on the side. Later ones were even better and had 'DX'. Other key differences: rods were a bit shorter to accommodate the diesel pistons. Crank main journals were bigger too. 3" vs 2.5" for the gas.

[JMac11]

Lots of guys swap gas heads for the diesel heads. Everything else bolted on. Did not like cheap gas, spark knock. You had to drill out the gas heads to fit the diesel head bolts. GM did not change the cam design, so your gas distributor ran off the gear drive that ran a vacuum pump on the diesel. Cams had roller lifters too. Never knew how it turned out, but you could mix and match parts, diesel block, Olds 425 (yes 425) and 455 rods and make some stroker engine that was supposed to be bullet proof and make trq/hp.

[GASoline71]

Mondello Performace used to so some wicked stroked out Olds engines using the diesel blocks.

Gary

[BossHogg69]

Originally Posted by GASoline71

Mondello Performace used to so some wicked stroked out Olds engines using the diesel blocks.

Gary

Joe was a straight up guru and super nice guy to boot - he was always wiling to share his years of knowledge and experience. I first met him in 2004 at the PRI show.

[GASoline71]

Always wanted to meet the man. I still like to read all the Mondello Performance literature I can find.

Gary

[RustyBucket]

Long time ago I got a great deal on a loaded '79 Silverado SB 'cause it was a 5.7 diesel. I clattered around for awhile and swapped it out for a 455 out of a '71 Toronado. Everything bolted up easily. I added an O4B alum. intake, 750vac. Holley and a Melling copy of a W-30 cam. SERIOUS TIRE BLASTER.... serious gas hog too. Had 2 16gal saddle tanks.

[garmar]

Helped a buddy put a 350 Rocket in his 78 Scottsdale. Bolted right up because it was originally a diesel. Thing pulled like a freakin freight train.

He had a spare 403 Rocket sitting under a tarp for years and one day the 350 sucked the air cleaner bolt and we dropped the 403 in. The thing was amazing. I would take one over a SBC all day long.

[dennislbrooks]

A lot of good info above. I have an 70 olds 442 with a 455. I am pretty sure the 455 gets most of its added cubes by being a tall block 350 and bigger bore. Intakes will not interchange as the 455 intake is wider. Comparing the physical size of the 455 to my bbc in my 67, the 455 is like picking up a small block. I like both engines with the 455 having 500 ft lbs I think at around 3300 rpm. My bbc 402 is no slouch either with gobbs of low end also.

The 455 needed an OD so I added a 700r4 ----- now a real 442.
The 402 needed an OD also and got a 700r4 ----- nice.

just rambling.....

[GRX]

Purely for the sake of conversation, here is a page that compares weight & various dimensions of many common American V-8s. Seems reasonably accurate from what I have seen over the years.

Interesting how the Olds 350 is both wider and lighter than the Chevy 350.

>> http://www.carnut.com/specs/engdim.html

As an aside ... BBC and Pontiac V-8, of which there is only one block size regardless of displacement, are about the same overall dimensions. But do not dare call a Pontiac a big block. Drives a lot of those arrowhead guys crazy!

[61_FL_Apache]

Originally Posted by clinebarger

The Old's 350 diesel was installed in some 1/2 ton trucks.

Those engines were dogs!! my parents had a pair of them in an 85 Caddy and 85 Cutlass... Bad idea for GM.

[Eddie H.]

I was working at a GM dealer back in those days, and I remember the 350 Giesel well. My boss bought a new 1/2 ton pickup with one, and had to park it on the street, because it didn't have enough power to get up into his driveway.
Under warranty, GM wouldn't let us replace the engine unless it was a total failure, so when we had one with a problem, we'd just park it out back and put a brick on the gas pedal and walk away until it got quiet.

[LT7A]

This is one of those posts where I don't have anything but anecdotes to add -- so feel free to pass on by, ha. The thread intrigued me since I've owned a '71 Cutlass S with a 350 since 1986. I also have a 455 on stand, waiting to be rebuilt. My folks have their 1970 Cutlass 350 they've owned since new. My dad went through a 1981 Toronado 5.7 diesel, so we got to experience that awesomeness too, haha. I don't think I would swap an Olds 350 into a truck just because. But if it was an Olds based diesel previously and needed a new motor I would do a 350 or 455 in a second. Definitely will pay a lot more for hi-performance parts though than you would for a Chevy SB/BB.

Originally Posted by BossHogg69

Joe was a straight up guru and super nice guy to boot - he was always wiling to share his years of knowledge and experience. I first met him in 2004 at the PRI show.

I bought a bunch of stuff from Mondello Performance back in the early aughts and talked to a helpful guy named Lynn. Last summer at the NHRA Northwest Nationals I saw a bunch of folks with Mondello shirts and asked them if they had a booth. They said no but to come by their motorhome and say hi. So when the races were over for the day I went by and talked to Lynn Welfringer for awhile. He was Joe Mondello's business partner. Joe is gone now but Lynn still sells a ton of parts and complete motors. His daughter works with him and they get out to do quite a bit of racing. I have family a couple hours from their shop and he said to come see him and get the tour if I can. I never talked to Joe, but Lynn is a cool guy. Very personable and knowledgeable.