Barn-Find 409 Engine Rebuild - Unearthing A Legend, Part 1

We Take a Mysterious, Barn-Fresh 409 and Turn it Into a Performer.

Tommy Lee Byrd May 7, 2014 0 Comment(s)
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In the Chevy world, very few engines have the wow factor of a 409. Be it a bone-stock restoration or a high-end race engine, the allure of a 409 lies in its unique design and rarity. When Chevrolet introduced the W-motor in 1958, it had a displacement of 348 ci and an odd appearance compared to the standard small-block Chevy, which had only been available for three years at that point. The 409 was introduced in 1961, and it was an evolution of the 348 design, utilizing a larger bore and a longer stroke.

The strange shape of the cylinder heads and valve covers makes these engines easy to spot, but there are lots of other differences that make the 348 and 409 unique. While it didn't take kindly to high rpm, it was a very popular engine combination in the 1960s. That's where our engine comes into play, as it once lived a tough life on the dragstrip. It was the motivation for a '55 Chevy drag car that ran in the Chattanooga, Tennessee, area in the mid-to-late '60s. The car was built and raced by Don Roberts of Graysville, Tennessee, but Don passed away a few years ago, so some of the details regarding the engine are fuzzy.

The casting number on the rear of the block (3830814) tells us the engine would normally be found in a '63 Impala. However, we noticed a peculiar detail as we continued to run the numbers. Like most Chevy blocks, the stamping pad is located on the front passenger-side of the engine. As we scraped away gunk and paint from the area, we couldn't find any numbers or letters—nothing. That told us this block had either been decked or it was an over-the-counter block. To get our answer, we rubbed muriatic acid over the stamping pad, as that can usually show the codes, even if the block has been decked. At this point, we still had not disassembled the short-block, so we did not have proper access to measure the deck height to double-check. After all of our theories and testing, we determined the block was an over-the-counter purchase.

As we continued to scrape around and find details on this engine, we filled the cylinders with oil and let them soak for a few days. Before starting the disassembly process, we wanted to turn over the engine, and we honestly did not know what to expect. We didn't know if it would be stuck due to a 30-year stint in a barn, but it required very little effort to get it spinning again. So far, so good.

409 Engine 2/26

This is how we found the 409. All of the parts around it—including the oil pan—are 348 items, leading us to believe this engine may have been a cheater in the '60s. Luckily, all of the parts were stored indoors for 30 years.

Disassembly provided a couple of other strange details. The crankshaft casting numbers were barely visible, appearing to have been ground off, leaving only the last two numbers of the code: 72, which is the end of the 3788072 casting number. This designates a '61 crankshaft, which from our research, is no better or worse than any other 409 crankshaft. The high-performance 409 engines featured a windage tray, so the third and fourth main caps featured extra-long studs instead of bolts. These studs were in place but had been cut off flush with the main cap nut—an odd modification, but they obviously had some sort of reasoning behind it.

By far, one of the most peculiar aspects of this 409 was the assortment of parts that came with it. We have no way of confirming any of our speculation, but we can confirm that every single part that came with the engine was 348 equipment. Even the oil pan was a 348 piece, making our minds wander into the years of "it ain't cheatin' if you don't get caught" drag racing in the Southeast. Was this a cheater engine, claiming to be 348 ci, when it was really a 409? All signs point to yes.

The casting numbers would have given it away, but Don's '55 Chevy was allowed a 10 percent engine setback in the gas classification. That means the rear of the block would be tucked in tight against the firewall, making the numbers impossible to see. The block had no stamping codes, so the tech guy had no ammunition there. With 348 cylinder heads, intake manifold, and oil pan, this 409 could've been a wolf in sheep's clothing.

So if all this is true, why would a racer go to all this trouble to say he had a smaller engine? In the '60s, most classes were separated by the weight of the car and the (claimed) cubic inches. If you had a car with big cubic inches (such as a 409), you'd likely be forced to race in one of the faster classes such as A/Gas or B/Gas. However, if you had a smaller engine, like a 348, you could squeeze into a slower class, such as D/Gas and clean house, especially if that 348 turned out to be a 409.

Regardless of this engine's history as a drag racer, it proved to be quite resilient. As we disassembled the engine, we kept thinking, "There has to be a reason he took this engine out of the car." We expected to see at least one chewed-up journal or a scarred cylinder, but no, we found zero flaws in this barn-fresh 409 short-block. An unbelievable find, this 409 only needed a simple rebuild to be ready for action once again.

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