bspaulding

You all refer to big and small block engines but what is the 303/394 series referred to? Middle block? Original block? I have found threads for the 371 in the big block section but it isn't really. Is the small block just a Chevie small block 350?

Remember---no stupid questions.....so be nice.

redoldsman

When most Olds people refer to a small block that are talking the Olds 350 and big block is the 455. The most common terms are Olds 350 and 455. The first generation Olds engines are the 303, 324, 371 and 394. You are correct that a 371 is not considered a big block. They most often are referred to by their displacement.

don71

Its my opinion the terms small and big were partly to be blamed on Chevy and its offerings.

The generation you refer too, had never heard those terms before magazines populated them years later, kinda like the term posi or positrack.

Even with other makes, they have their big and smalls. Some of the time it can be referred to low deck or tall deck, within the same engine architecture.

This doesn't mean they used the same casting. The only way to make an engine bigger is with bore or stoke. The casting has to accommodate that.

I've added only my opinion on this, not knowing what or how the Olds engineers did this in that time frame you ask. Those engines of that era have some compatibility, but its limited.

1969w3155

An Olds 350 shares nothing with the Chevy small block other than cubic inch size, they are a totally different design, sharing no parts.

quaddriver

I guess what throws people off, is that a 'small block' olds, is externally dimension-ed larger than my big block chevy 454. So if we lived in a chevy centric world (which sometimes we do) I have heard people call it a big block 350. Next to a bowtie it certainly looks the part and this was a major contributor to the demise of olds as a powertrain manufacturer.

The 455 olds is decked higher, but its not like one is cut more at the heads than the other - it is a unique casting, using many of the same mold dimensions.

other car makers were similar, especially ford with 289/302, windsor, cleveland, FE, MEL, 335, 385 etc designations.

when money was good, standardization was out!

MDchanic

As noted:

First Gen V8: 303, 324, 371, 394
Small Block: 260, 307, 330, 350, 403
Big Block: 400, 425, 455

First Generation was an immediate-post-War design, with an integral bellhousing.

SBO/BBO were short and tall deck versions of the same design -
Differences:

• Deck height,
• Main bearing diameter,
• Fan belts (to accommodate deck height),
• Manifold dimensions (to accommodate deck height),
• Head intake port dimensions (but heads can be interchanged physically, provided head bolt sizes, which changed in 1977, are the same),
• External parts, sometimes (cams, distributors, carbs, vibration dampeners).

Don't mention the C-word here.

- Eric

joe_padavano

First of all, there is no "legal" definition of big block or small block. Common usage in the Olds community is to refer to the short deck (260, 307, 330, 350, 403) second gen motors as "small block" and the tall deck (400,425, 455) as "big block". This is for convenience only as these are really the same engine architecture with different deck heights. I like to think of them as the same as the Chrysler B and RB motor families (383 vs 440, for example).

The first-gen Olds V8s actually have THREE different deck heights over the years, the 303/324, the 371, and the 394.

BlackGold

Wow. Now that's a controversial statement on several levels.

bspaulding

WOW!!!

Did I stir up a discussion! I really like the term First Gen. Concise and I want to be first with my FIRST GEN 371. Wow!

As a FORD guy who just did a '50 Olds (my first real car in the day), I understand not using the C word on an Olds forum.

I also agree re the many confusing Ford iterations of engines. I put a 302 crate motor in my 56 Victoria and they have at least 5 different water pumps for that motor. One for every day of the week? My 33 Ford Tudor has a 351 windsor and my 27 Ford T has 2.0 German Pinto motor. The spark plug wires can interchange but not much else...

Anyway, Thanks guys---it clears up alot for me.

Bill

joe_padavano

Huh? What fun-house mirror are you looking in? The SBO is two inches shorter in length, three inches shorter in height, and one inch narrower than an standard passenger car BBC. The SBO also weighs about 120 lbs less.

FYI, the Olds 350 also has a shorter stroke and longer bore than a Chebby 350.

quaddriver

perhaps, but I am quoting something I read years back in C&D when 'gm powertrain' as we know it was reformed. the sheer size of the non chevy stuff handicapped the designers as to how small they could go. the emphasis was on weight savings, aero concerns etc. if you recall, the SBC DID get turned around sideways in the FWD cars, first gen 1, then LS1. it would have never worked with the old iron. plus the weight was more, lack of aluminum, lack of engineering support etc.

If anyone alive in the 1975-77 era reading this now didnt see the writing on the wall then when the whole 'engines produced by other divisions' disclaimer came out, they were not paying attention. as a company, GM telegraphed its moves over 10 years in advance. thats why there was never an attempt to TBI or TPI any olds v8s (horrible cadillac version be damned)

quaddriver

Clinton?

joe_padavano

Wanna bet?

quaddriver

yessir, what production car was that installed in? (re-read last sentence of last post) I had a working MFI system for a 350 in 1986, but Im pretty sure that didnt count either.

q) what was one of the last carburated engines in the US?

q2) why was it not TBI while every single other offering from the same company was.

I mean if we follow that line of reasoning, there was no such thing as a 6-71 blowered gasoline car engine from gm, but I can buy intakes for that also.

quaddriver

You are right, I was using hyperbole, the critical dimension is side to side and I should have said 'similarly', since just about every RWD car has an I-6 option, the length dimensions were mostly uninteresting, but side to side....dictated strut towers, cowling, frame rails, FWD considerations etc (read: no big blocks in van, heater core interference on cutli ;-) etc)

the mouse, fit the best. the mouse and only the mouse survives today. total coincidence?

1969w3155

because Olds was meeting emissions standards with the carburated 307 which no one else could do.

joe_padavano

My point was that Olds WAS developing a TBI system for the 307, hence the factory experimental intake in my photos above. The project was killed when GM dictated that the Chebby motor would be the only RWD V8 after 1990.

I'm not sure why you have discounted the EFI Olds 350 from 1975-79. The "horrible" part of it was the limitations of the computer technology of the time, not the motor. It was arguably far more sophisticated than the TBI motors that didn't come out for another decade. Unfortunately the rudimentary analog computer that ran it was a turd.

Also don't overlook the fact that every single Olds Aurora V8 was EFI...

quaddriver

corrected: which no one else even tried, because, well, why would they.

I know that GM threw exactly zero dollars into the wagons and the non-chevy big cars because FWD replacements were all over the place and the whale was in the works - the big poncho, buick and olds already had a fwd replacement using the, once again, much more powerful and cleaner 3800.

but consider this, if they HAD instead just scrapped the warehouse of 307s in stock and replaced them in the cars with 4.3L Z motor v6's, which were TBI, now only could they have used the much better 700R4 tranny, but the car would have had more hp, more torque, better driveability, less emissions...those are all wins.

quaddriver

well it was not a hard choice, not one other division was any longer producing v8s other than caddys own pre-northstar junk and they had to look at the economics: since 86 gen1+ was out, it could run LEV, it had a lot of new engineering, LT1 was on the test track....the 307 was still stuck having been engineered in 1969, just like the chevy 262 and 400 died -they could not meet emissions to come. OBD2 had a mandate date on the books and there would have been too much cost to play 20 years of catchup. reality vs nostalgia

for the same reason I discounted everyone elses EFI as well, until the engine controls got to a point of reliability, the end result was something that just did not work - period. nothing irritates a car owner more than sitting in the dealship waiting room.

But note, by 87 everything was EFI, even the last 4bbl left the ford trucks. If you worked in lansing in 1987, you were checking your early retirement options.

That is true, but the one size only solution was too little too late and it bears noting that it shared zero in terms of parts and more importantly engineering with the motors it was to replace. completely different development program.

joe_padavano

As opposed to say, the LS family at Brand C, which shares SOOOO much with the heritage SBC motors.

What is the purpose of this whole tirade anyway? Are you trying to justify putting an SBC in an Olds or something? GM made a lot of bad management decisions in the 1980s based on bean counting. The cars were built like crap, they weren't even trying on design (every 1980-1990 B-body wagon uses Chevy sheet metal from the firewall back), they cut corners on the electrical systems with undersized connectors and wiring (delete the relays on the power seat motors but don't upgrade the switch contacts to account for the higher current through them???), the list goes on.

quaddriver

well this is a whole thread in itself, LS is a natural followon but anyways...

no sir, it was suggested my assertion that status quo from olds led to them not being involved in GM powertrain would be somewhat controversial.

Perhaps GM mgmt is to blame, but certainly the lack of any desire to change the current reality was the main driver. things shook out the way they did because it was a natural order. sure, we have soft spots for those old cars, but the car company left us first and dont forget it. when the answer to save weight was window the mains, people should have questioned that at the drawing board.

just look at the history of how the powertrains fell, the order, the sizes. you telling me that only chevy engineers had the smarts to get a 7+ litre motor compliant? I recall when but a kid of 13ish my dad telling me the whole 'engines produced by other divisions' protest was silly, as he put it, the chevy 350 (the spat was really 350L vs 350R (olds) vs 350X (buick) vs 350P) was a better engine. it was, we all know that now as a general populace know what the engineers knew then. why? why did it have to be that way? I think the R motor got to live slightly longer simply because the cutlass was the best selling vehicle on the planet. but why was it such an easy decision to make? however you are right, we are long off the rails, into the weeds, your answer to the OP was well written and adequate....my apologies. we can take this up further around my campfire at carlisle in 3 weeks...

joe_padavano

The only EPA compliant 7 liter car engines (keep in mind that truck engines are held to a different, less stringent standard) have been LS motors within the last 5-10 years. Again, it hasn't been the almighty Chevy engineering that allowed that, but the advancements in processor power, cylinder head design, computer modelling, and advanced catalysts. The fact that GM killed off all other V8s except for Chebby motors (and even the BBC ultimately got axed) has more to do with economics than either basic design goodness or engineering prowess.

Geeze, at least I was driving my 425-powered Vista Cruiser and building my 68 442 in 1977...

I agree that the whole engine swap lawsuit was simply a way for class action lawyers to get rich (no one complained about Chevy six cylinder motors in other divisions' vehicles), but the "better engine" claim is one I'll argue. I have no delusions that the SBO is any better or worse than the SBC, but most of the SBC popularity is due to better aftermarket support (yeah, it's chicken-and-egg...) than inherent design. No one will argue that stock Olds exhaust ports suck, which is one of the most limiting factors of that architecture, but as I noted above, the 350 Olds has a shorter stoke and larger bore than the 350 Chebby. When Olds got serious with the NASCAR blocks and Batten heads, they were even competitive in NASCAR. Unfortunately, there was a lot of ground to make up and not enough money to do it.

One of the biggest missed opportunities was Oldsmobile's inability to capitalize on their racing sponsorship in the 1980s and 90s. Olds won the NHRA manufacturer's cup every year from 1984 to 1995, thanks to their extensive sponsorship investments. Olds also dominated IRL and the Indy 500 for years. Unfortunately, these winnings (and underlying investment) were never publicized to the car-buying public. Yeah, Olds ran ads in National Dragster and other motorsports publications, but those readers already knew about it. How might things have changed had Olds done a better job of blowing their own horn?

I've got the beer. I'm afraid it's closer to four weeks, however.

quaddriver

damn, stabbed in the heart...