Cai paez

I have a 1978 Oldsmobile Cutlass, and I'm trying to figure out what size motor it has. I believe the casting numbers are: 2A 558916. Any help would be appreciated.

CRUZN 66

Welcome to the site...
The 2A makes reference to the 260, but the 558916 is not listed...
If the engine is original to the vehicle, the 5th digit of the VIN will identify the actual engine installed at the factory...

joe_padavano

The ONLY gasoline Oldsmobile V8 installed in a 1978 Cutlass would be the 260, which is what you have. The cylinder heads will also have a 2A on them. I'm betting that the fifth character of your car's VIN is the letter "F", which also indicates the car was born with the 260 motor.

Allan R

That's simply not true. In 1978 olds ran out of engines for the Cutlass model and some were produced with Chevrolet 305 4bbl V8.

I will concede that the vast majority were the 260, but certainly not ALL. Absolutely the VIN will tell the tale if the engine is original.

joe_padavano

Allan,

Time to brush up on your reading comprehension. From above:


The Chevy 305 is not an "Oldsmobile" engine. The diesel 350 is not a "gasoline" engine. Both were offered in 1978. Neither applies to the OP's car nor my statement.

Note that I did NOT say "the only V8 Oldsmobile installed".

CRUZN 66

According to the 1978 CSM the 305 code H and the 350 code L are also listed, in addition to the 260...

Allan R

Point taken, although not comprehension, more attention to detail. I should have said chevmobile or Oldsmochev engine....
Here's a question though. Why couldn't a special order 1978 Cutlass have other than a 260?

Btw, I never said anything about the diesel.

joe_padavano

The LM-1 350 was a Chebby motor also, so again, the 260 was the only GASOLINE OLDSMOBILE V8 offered that year in the A-body line. My statement stands.

joe_padavano

Because by the late 70s, automakers could not legally sell a drivetrain that had not been emissions certified in that particular chassis. Obviously Olds did certify the 350 Olds motor for the 1979 H/O, but that was not the case in 78.

Never said you did. I was just trying to be excruciatingly complete lest someone else point out that there was ANOTHER Oldsmobile-sourced V8 available...

CRUZN 66

Not disputing your statement or your post Joe, simply providing info to the OP as to "all available options" per factory listings... Since the request wasn't to identify ONLY Oldsmobile engines (he was unsure of actual casting number), the additional info is simply that, info... I do agree, I believe if it is a V8, it is most likely a 260 if factory original, hopefully he will be able to determine that from the info being provided...

joe_padavano

Understood, but the "2A" and "558916" are Oldsmobile casting numbers. I was also kind of assuming the OP could tell the difference between an Olds motor and a belly button motor, but yeah, that is an assumption.

Allan R

I find that interesting because I bought a 1978 Cutlass Calais off the dealer showroom wit the Chev 305 4bbl. I'm guessing that when you say Chassis you're referring to only the rolling chassis, which would have been shared with the Malibu? Btw, that was a nice performing engine.

I wonder if emissions requirements were different for Canada back then.

joe_padavano

I don't understand your point. The 305 Chevy WAS emissions-certified in the A-body line for the 1978 model year. It was available in the Cutlass line as a regular production option. There was no "special order" needed, just check the box on the order form.

Or are we going to argue about the definition of "special order" again?

And yes, in 1978, Canada DID have different, less stringent emissions requirements than did the US - and that difference continued into the 1980s. As an example, the 307 did not get CCC on cars sold in Canada until the mid-80s. US cars got CCC starting with the 1981 model year.

Allan R

No, Joe. I don't need to revisit that. Let me TRY to be really really clear. I was wondering IF, since you claim that " ONLY gasoline Oldsmobile V8 installed in a 1978 Cutlass would be the 260" , couldn't the L34 or L80 could be "special ordered" even if it wasn't a check box item for that model??? I get that there are RPO's for the model year and that the Olds 260 and Chev 305 engines were check box items in the respective models. BTW the 1978 Cutlass 442 does show the 350 option available as a high altitude option, whatever that is. What I'm still wondering is IF there was ANY concession given by dealer or Oldsmobile to have a Cutlass model ordered with the Olds 350 or 403 in 1978. The brochure * simply states "Check Salesperson for axle ratio availability with various models and transmissions". To me, that doesn't discount the possibility of an RPO that wasn't generally offered to the Cutlass line-up. We both know that brochures don't provide ALL the information, just the general information that the non discerning customer would look at.

I would hazard a guess that more cars in Canada were equipped with non Olds V8 Chev power than in the US. I remember how underwhelmed I was with my 1982 Cutlass Supreme's 260.

Yes, I thought so. My 1983 98 Regency Brougham didn't have any of the CCC equipment. I believe it came into play here in 1985, because I remember looking at a 1984 98 Regency that didn't have it either. Lucky us.

Cai paez

​​​​Thanks to everyone who shared their knowledge. I can now buy parts to keep another Oldsmobile cutlass alive.

CRUZN 66

Did you determine exactly what engine is in your 78 Cutlass???

Cai paez

Yes I determined that the Motor in my Cutlass is in fact a 260 V8, although my Cutlass has an H code vin# and Originally contained a 305 c.I. 5.0 liter Chevy motor. Also thanks for the Welcome.

joe_padavano

Again, no. It was against federal law. By the 1978 model year, automakers faced a significant fine (and possible criminal action) if they sold a car that did not comply with EPA certification requirements. The engine had to be emissions certified IN THE PLATFORM. The fact that the 350 or 403 was certified in the Delta 88 did NOT make it legal in the Cutlass.

I'll point out as an aside that cars like the modern Mustang Cobra Jet and COPO Camaro are NOT emissions legal and do not come with VIN tags. They are factory built race cars that carry non-certified engines with no emissions equipment and thus cannot be legally driven on the street - at least, not in the U.S. This makes the new Dodge Demon that much more impressive, as it blows those cars away and STILL complies with all US emissions and safety laws. I'm both pleased and amazed that FCA produces that car.

joe_padavano

WOW! I'm amazed that someone would go through that trouble and drop in a 260! Out of curiosity, can you read the VIN derivative stamped on the block?

btw

Before everything gets lost in translation/interpretation/understanding/original points/misinterpretations/revisting old posts/clarity issues/missed points/etc:

Welcome to Classic Oldsmobile! I hope you enjoy your stay here, find useful and interesting information about your Cutlass, and enjoy your car for years to come!