Five Weird Facts About the Chevy Small-Block V8

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Just for fun, here are some colorful facts about the Motor City’s most ubiquitous engine.

 

We don’t know who counted them, but it’s said that over the past seven decades, General Motors has manufactured more than 100 million examples of the Chevrolet small-block V8. And not just for Chevrolets, either. The ubiquitous V8 has been used by every U.S. car division at GM except Saturn. (And used by two non-U.S. GM brands, too: Opel and Holden.) Naturally, an engine that popular would generate a ton of colorful gearhead lore, so here are five interesting facts about the small-block. No doubt you have some SBC lore of your own, so please feel free to share in the comments section below.

 

1)  When the Chevrolet V8 was introduced in 1955, your typical Detroit V8 (Cadillac, Chrysler, Pontiac, et al) used 10 bolts per cylinder bank to secure the cylinder heads in place. However, the SBC uses 17 head bolts per side, in part to provide a better gasket seal. This arrangement (torque sequence chart shown above) also reduces cylinder bore distortion when the head is torqued in place. With 10 bolts, the cylinder is pulled into a square-ish shape, but on the Chevrolet the shape is closer to a pentagon, and rounder bores promote improved ring seal.

 

2) Have you ever seen a chartreuse Chevy V8? In 1957, it was actually a factory color. The Chevy V8 was enlarged from 265 to 283 cubic inches for ’57, but the 265 version remained in production. To distinguish the two displacements, Chevrolet painted the 265s a bright chartreuse color until mid-year, when all the V8s were finished in the appropriate Chevy Red.

 

3) The small-block’s cylinder head is not only interchangeable from the left to the right banks; it’s also a “book-fold” layout. That is, the head casting (sectioned example shown above) is essentially symmetrical on each side of its vertical centerline. This  simplified the patterns, cores, and casting process. It also compromised the engine’s high-performance potential in some ways, but you can’t have everything.

4) In its half-century history in production vehicles, the SBC was  been manufactured in more displacements than any other Detroit V8. Let’s see if we can remember them all: 262, 265, 267, 283, 302, 305, 307, 327, 350, and 400 cubic inches. (The 267 and and 305 were small-bore V8s engineered for low emissions and fuel economy.) As much as anything, this variety demonstrates the small-block’s tremendous versatility as a production engine.

5)  Here’s perhaps the most intriguing fact we’ve included here: More than 65 years after it was introduced, the small-block is still being produced. While the engine was discontinued in production vehicles in 2002, GM’s Chevrolet Performance division continues to offer a full line of crate engines, blocks, heads, and components, and as we understand it, these are not remanufactured parts but brand new stuff. Below right, next to the ’55 Corvette 265 CID V8, is the ZZ6 350 crate engine, which sports a roller cam, electronic fuel injection, titanium intake valves, and other up-to-date features, and it’s rated at 420 horsepower. Just drop it in and go.

30 thoughts on “Five Weird Facts About the Chevy Small-Block V8”

    • Yes sir, and these engines include many of the improvements used in the Chevrolet Performance engines mentioned above.

  2. Don’t forget the factory issued 307, and the hot rodder’s modified 292,301, and 383.
    In spite of the limitations of the head design mentioned in the article, they had to allow more performance potential than the stacked intake ports of the contemporary Ford Y blocks, which is one reason why the little mouse was so popular with the go fast crowd.

  3. When calling on GM I met a guy working for a contractor. He was part of a team that designed the original 265. We had a long conversation and he revealed several things about the guidelines given for the design, one of which is the engineers were required ot use as many existing parts as possible in it, many came from the straight 6.. When Smokey was putting on the 25 year tribute to the guys that worked on the SBC design at a PRI show he asked for names of people that did. I called Smokey and gave him this guy’s name and phone number. At the event this guy was seated with the rest of the engineers that were still alive.

  4. I bought a brand new 55 Chevy with the then new V/8 and had much fun with it.Back from the service in 1959 I dropped a SBC into a 40 Ford coupe.I knew these engines were a big hit then and still are. I presently have a 37 Chevy coupe powered by an L.S. 5.3 Chevy engine. The adrenaline rush never quits. I should mention having the 305 H.O. in the 87 Monte Carlo while I’m at it.

    • Did the 57, 265 have the block oil filter provision? Seem to remember it did. Thinking that would be a rare piece for someone needing it for a nut and bolt restoration.

  5. an old Chevy mechanic told me that when they first came out,they burned oil due to unseated piston rings.he told me that added cleanser to the intake to solve[maybe] the issue

    • I knew a dealer who also had the same problem with Pontiacs. I think the problem was chrome plated rings.

    • Yep..Original 265’s used chrome rings,they took forever to seat,especially with impatient owners who couldn’t do 45mph for 1000
      miles..LOL!!..They slowly sifted small amounts of Bon-Ami Cleanser in the carb while running the engine at 2000 RPM’s or so,then did a few oil changes….I’ve actually done this over the years to a few Harley’s built by guys who thought chrome rings were a good idea,LOL!!

  6. Ifn I ain’t mistaken the 1948 Bel Air Impala had a 348 with friends power!! How could U forget that epic engine????

  8. Opal and Holden had SBC powered models. But later moved to 253+308 Holden sb later 4.2 Lt 5.0lt and 4.9lt 304

    • Holden Special Vehicles (HSV) also built a 5.7 Litre version with a stroker crank, that was fitted to VR-VT models from 93-99.

  9. If I remember correctly, the very early small blocks motor mounts were at the front of the motors block, and on the bell housing. The transmission was floating with no support.
    Chevy quickly changed this arrangement, but the motor mount holes were still put into the front of the block for years afterward.

    • That engine mounting system was used on all ’55-’57 Chevrolets and was optimized to reduce vibration. The system, also used on Ford trucks, works better than it looks because the torque reaction remains at the mounting point. When Chevrolet went to side mounts the bolt bosses remained for the power steering and other accessories. By the way, the upper right bolt hole has a second purpose. You can thread a long bolt in to hold the fuel pump pushrod in place while replacing the fuel pump.

      More on the engine mount setup here. https://www.macsmotorcitygarage.com/bow-tie-revolution-the-1955-chevrolet/

      • That trick about changing the fuel pump made it possible for me to change the pump on my ’67 283 in the street. I hear the later engines don’t have that hole anymore. No mention of it in the 1988 Chevy shop manual.

  13. 5 bolts per cylinder to hold the heads on is the key to a small block as a race engine,, and a very good oiling system. And the cooling is not bad either.
    For production road car engines hard to beat. BUT factory machining and castings can be terrible. The well known core shift leaving bores very thin on one side, heads with eons of casting flash around the guides. And at times some very wrong selective fit bearings.
    Meaning to simply recondition they need to be line bored as well as sonic tested. And more than a few min with a die grinder to clean up shitty castings.
    I would hope the later engines were better but probably not! The latest block I have used was an early 80s one.
    Here in Oz our Holden 6s and V8s were no better. I once had a crank that had one journal at 9 thou undersize!!
    Holden V8s had 5 bolts per cylinder on the cntre cylinders,, but the lug is weak and breaks when torqued to 70 lb, tension for that one is 55lb.
    Though the front and rear of the head gasket leaks water very often.

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