Packard Forum Index » V-8 (1955-56)

Apocryphal... or not? Detroit Urban Legend... I wonder.

Plans to morph Packard V8 into a Chevy BB circa 1958.

Over on the pre-war board was a post regarding a possibly true story that Chevrolet had more than a passing interest in the Packard "Big Block" design for their first BB engine. I thought I'd start a thread over here on the V8 board and present the question.

One possible scenario (speculation only): Given the rather odd-ball qualities of the Chevy 348 BB and other early "W" motors, perhaps Chevy was struggling to get out an all-new BB design to compete with their GM brethren, and "Studebaker Packard" could sure have used the money about that time.

If Chevy were to tool up for a version of the '56 Packard V8, massaged enough to look like a unique design, it would've taken them about two years of development to be ready for 1958, when Chevy introduced the 348.

Wouldn't it seem logical that with all the experience in developing the Cadillac, Buick, Olds and Chevrolet V8 engines behind them, GM would have had much more than enough in-house expertise without going outside?

FWIW, I got this first-hand from Francis Preve, the Chevrolet engine historian. Cheverolet needed a big block engine for the bigger, heavier cars and trucks to come. In 1957, GM had three studies under way:

1. Mark I study was to take the already designed and production ready 348" out to 427" and beyond. This block turned out to be too weak for the 500" they figured to need twenty years down the road.
2. The Mark III study was to buy the Packard V8 tooling for pennies. It could easily go to 500", but the marketing folks didn't want to be associated with a loser and the engineering department wanted the chance to try some new cylinder head ideas. They knew they could do better than a first-iteration Kettering knockoff.
3. The Mark IV study developed the cylinder heads which ultimately became the 396", 402", 427", 454", 502" and 572" big block Chevrolet, still in production today.

So bottom line, Chevrolet assigned an engineering number to a formal study of buying and using the Packard V8, but it went no further than the bean counters asking for it because it would have been less expensive. Marketing and engineering were the deciders and they said, "Let's invent it here." More than you want to know below:

thnx, jack vines


Mark I: The first big block Chevy, also called the W-engine perhaps because of the layout of the valves and therefore the shape of the valve covers--although another possibility is that GM chose the "W" prototype for production rather than the competing "X" or "Y" prototypes, and therefore it's a convenient coincidence that the valve layout is in the shape of a "W". It should be noted that this engine became known outside Chevrolet as the Mark I only after the Mark II was being designed years after the "W" was introduced. Whatever the origin of the name, this engine family was installed in vehicles beginning in 1958, as a 348". In 1961, it went to 409" and in 1963 a few well-connected racers could buy a 427". The 427" version was racing-only and had special parts which were not directly interchangeable with the 348"/409". While production of the 427" was limited, both the 348" and 409" were offered in passenger cars and light and medium-duty trucks. The truck blocks were somewhat different from the passenger car blocks, having slightly different water jackets and of course, lower compression achieved by changes in the piston in addition to more machining of the top of the cylinder. A novel feature of this engine is that the top of the cylinders are not machined at a 90-degree angle to the bore centerline. The top of the cylinder block is machined at a 16 degree angle, and the cylinder head has almost no "combustion chamber" cast into it. The combustion chamber is the top wedge-shaped section of the cylinder. Ford also introduced a similar design in '58 - the Mercury/Edsel/Lincoln "MEL" 383"/410"/430"/462". The "W" engine ended in 1965.5 when the 409" Mk I was superseded by the 396" Mk IV engine.

Mark II: This is more of a prototype than a production engine. It is the 1963-only "Mystery Engine" several of which ran the Daytona 500 race, and in fact won the 100-mile qualifier setting a new record. It is largely the result of engineering work by Dick Keinath. Produced mainly as a 427" but with a few 396" and 409" cubic inch versions, all in VERY limited numbers. The bore and stroke of the 427" MK II is based on the W-engine and is not the same as the 427" MK IV on which the heads are still in use. Even though it was intended as a NASCAR-capable engine, it had 2-bolt main caps. This engine was never installed in a production-line vehicle by Chevrolet It only went to racers in time to run at Daytona in 1963. The Mark II was a breakthrough cylinder head design using intake and exhaust valves that are tilted in two planes--a canted-valve cylinder head, nicknamed the "semi-hemi" or "porcupine". The engine was the subject of an extensive article in the May 1963 Hot Rod Magazine. Because of NASCAR politics, Chevrolet was forced to sell two 427" Mark II engines to Ford after the '63 Daytona race to prove it was a production engine, and therefore eligible to race in NASCAR events. Thus, the Mark II is the grandfather of the Mark IV and later big block Chevys, it's also the grandfather of the canted-valve Ford engines: Boss 302", 351" Cleveland and the 429"/460" big block Ford.

Mark III: An in-house study on the feasibility of buying the Packard V-8 engine tooling. The Packard engine was truly huge, having 5" bore centers; bigger than any engine GM would build for the next twenty years. The former president of Packard wound up at Ford after Packard folded, perhaps because of that, Ford was also interested in this engine. Ford wanted to make a V-12 variant from it just as Packard had once envisioned. One way or another, neither GM nor Ford actually went forward with the purchase.

Mark IV: The engine that most people think of as the "big block Chevy". Released partway into the 1965 model year as a 396", superseding the older 409". It is a development of the Mark II cylinder heads, using similar but not identical canted valve (semi-hemi/porcupine) layout. It was later expanded to 402", often still labeled as a 396", or even a 400", 427", 454", and a few special engines were produced in the late '60's for offshore boat racing as a 482". There was a 366" and a 427" truck version that each had a .400" taller deck height to accommodate .400" taller pistons using four rings instead of the more usual three rings. These tall-deck engines were used only in medium-duty trucks (NOT in pickup trucks--think in terms of big farm trucks, garbage trucks, dump trucks, school buses, etc.) The tall-deck blocks all had 4-bolt main caps, forged crankshafts, and the strongest of the 3/8" bolt connecting rods. All-out performance engines used 7/16" bolt connecting rods, along with other changes. This engine family was discontinued in 1990, with the redesign, known as the Gen 5 appearing in 1991.

(From Fran Preve and other internet sources, edited by JV)

THe "W" engines 348 and 409 were specifically designed for heavy truck use. YES, they were also used in passenger car but were never intended for passenger car. Correct me if i'm wrong but the "W" was never offered in Corvette. IIRC the valve cover is more like an "M" rather than "W" unless standing on ones head. "W" is just WIDE engine.

The very early 348's were real bad about breaking crankshafts. IIRC it had something to do with manufacturing process of the crank. Ed Rinke and MAthew-Hargreaves CHev Dealers of Detroit area sold a rather large fleet of 58 Chev Dumps to a local contractor. Nearly all of them broke cranks within a week or month of delivery.

The 454's were also never intended for passenger car use. They were intended for TRUCKS. Chevy built so damned many of them for some reason that they didn't know what to do. So, they put them in passnger car and Corvette.

The BIG BLOCKS regardless of ANY vintage or ANY manufacturer are grossly misunderstood engines. They are TRUCK engines or just plain drag racing engines. THEY are sprinters!!! Trucks and dragsters are not expected to have any longevity or endurance. They only have to deliver the load and in a rather short period of time.

One thing is for sure, the "W" (if they could keep cranks in them) were far superior (in power) to the glorified 235 Blue Flame that was used in the 54's and earlier trucks or even the Industrial Ford flat head version in Ford trucks.

The "W" was only a transition-of-era engine for TRUCKS. And basically a piece of shit on a par with Vega engines.

Enter the new era of Diesel for trucks a few years later.

PackardV8: I know that back when I was kid in the early 60's the Chevy 348 and 409's had a bad reputation for not being a good engine. Some people used to say that they made good boat anchors.

If I remember correctly the 348 engine was introduced in 1858 and was continued through 1964 boared out to a 409 cid in 1961 and dropped in 1964.



John F. Shireman

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WOW! 106 years! They really milked that engine! j/k

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Yes, John, and a lot of the time it's Chevy people who make cracks like that about Buick, Olds, etc. big-blocks. For a laugh some time look up some of the actual weights and even the supposed "small block" Chevy will be heavier than some of the competition's BB.

What Packard V8 says for the most part is true, these were Chevy Truck engines, designed at a time when Chevy was considering going all out with gasoline powered heavy trucks and even over-the-road tractor trailer rigs to compete with the diesel rigs.

Not only did they eventually give in to the other diesels, but GMC beat GM itself with the civilian version of the "Jimmy" 2-cycle. A real hairy monster.

Why did Chevrolet insist on dropping the BB in cars? Horsepower wars, I suppose. Get-em-up 409. But it sure did make for some nose-heavy rides,

V8's post also mentioned the only engine offered in the debut Corvette... first answer gets the prize... a chance to try to find anything amiss in Jack's writeup. It won't be easy. Good luck!

Jack, thanks for the verification of the Packard V8/Chevy BB rumor, and thanks to Turbo Eric for putting the bug in my ear leading to this thread.

Some more fun Packard trivia to perhaps expand upon if more info comes to light.

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A 235 cid Chevy straight six with three Carter YF carbs.

Olds built a 301 cid V8 sometime very early 50's. A relatively small overall engine if i remeber rite. But Chev had no V8 until 55.

In the 52-53 time frame of Corvette DEVELOPEMENT a few of the engineers argued for the Olds V8 in the 53 Corvette but Ed Cole (General Mngr of Chev at the time) wouldn't allow it. So the 53-54's got a HOT version of the chev. 235 6 cyl.

I suppose the best answer given so far for the original question as this thread is titled is the answer from Owen.

OR, at best, if Chevy was considering Packard V8's then most likely it was the TRUCK group and not the car or corvette group.