Vintage Engines: Chevrolet's "W" Motor

W Motors In Street Rods Today
Compared to the Mopar poly motors of our previous vintage engine story, the 348s and 409s are eminently practical for powering today's tradition-oriented street rod cars and trucks. In fact, there has been a rebirth of sorts in new components available for these engines. With their size and distinctive look due to the W valve covers, they are crowd-drawing in appearance, and in a macho way rather than pretty. They look like they could tap-dance over any SBC crate motor, and, with modern components, you can build all the horsepower and grunt your wallet will allow.

As far as installation goes, the Ws are wider than a small-block by about 3 inches and carry an average dry weight of 660 pounds, which is about 70 or 80 pounds more than a typical 327-350, although an aluminum intake, aluminum water pump, and tubular headers could trim off most of that. Stock motor mounts are on the side, but if you needed front mounts for steering box clearance, the old Hurst "saddle" mounts were drilled for both small-block and W motor bolt patterns, or you could easily fab some front mounts yourself. The Ws are also 2 inches longer than a small-block, so they probably won't readily work in a Model A without a firewall recession. They do have a rear-sump oil pan design, which is a big help for front crossmember and/or tie-rod/cross draglink clearances.

As for availability, this is one of the more available candidates out there in the micro-world of vintage engines for hot rods. Chevrolet made a lot of 348s and a fair amount of 409s, as well. As with any other cars of this period, ones with the high-performance options are much harder to locate, especially if all you want is the engine. The 409s are coveted by those fans who are restoring the fullsize Chevys the W motors came in; some 409 cars have shown up over the years, but their powerplants are missing. Thus, the restorers of these models are more motivated to find loose 409 engines and are liable to outspend us street rodders. Even without coveted numbers-matching status, their cars are worth more with the 409 in there.

For our purposes, the more available 348s can offer plenty of punch for a 2,500-pound street rod with street tires in back. To all outward appearances, all the W motors look the same, unless you're an expert with a book of casting numbers in hand, so the vintage look we want is there, regardless of the displacement. We recently saw a freshly rebuilt 280hp 348 motor, with rebuilt original Tri-power (shown running on a stand) for sale for $1,800 on eBay. Surprisingly, it didn't meet the reserve, but someone missed a truly great deal when you figure the cost of a long-block rebuild alone.

If you're up North scouting around, it's a little-known fact that Canadian-assembled Pontiacs also had Chevy W motors. Look for 348s and 409s in trucks, too. These had lower compression, but that can be altered to regain performance (note the exception above, and avoid the '58-61 348 truck engines). We've seen a few Ws at recent swap meets for decent prices, too.

Building And Dressing The Ws
As with any of the vintage engines we're addressing in this series, rebuild kits-from just gasket sets to kits with gaskets, rings bearings, pistons, and other parts-are readily available from parts houses like Egge Machine, Kanter Auto, Tracy Performance (Detroit, Michigan), and Show Cars (New Ulm, Minnesota). Two specialists in performance engine components, Bruneau Performance (Canada) and Lamar Walden Automotive (Doraville, Georgia), take all this to the limit with custom-forged pistons, stroker kits to 450 ci and more, and all the power parts you'd need for serious racing with a W motor. If you have a 348 and can find a 409 3.5-inch-stroke crank, it's a complete drop-in with the correct pistons. If you have the 409 rods and crank, they can be used with the stock 348 pistons.

One aspect that held back these engines in the old days was their extremely heavy cast pistons that limited their rpm potential (409 pistons weighed about 830 grams). Today, you can get a variety of forged pistons with your choice of compression ratios. A good engine balance job has the piston/pin weights within a gram or two of each other, but these modern pistons can save almost 200 grams per piston! You won't need the 4.11 or 4.88 gears guys used to have to employ to get a 409 to rev.

It's a miracle, but there are three new aluminum cylinder heads made for these engines. Bruneau Performance and Lamar Walden Automotive both have high-flowing heads designed for maximum performance, while Edelbrock now has its own Performer RPM street/performance heads with 7/16-inch rocker studs, guideplates, stainless 2.19 intake and 1.72 exhaust valves, bronze guides, and ductile-iron seats. To go along with that, Edelbrock also has aluminum water pumps, a dual-quad intake manifold, and the company is also remaking its finned, cast-aluminum valve covers. One rodder we know was quite upset about this, since he'd recently paid $375 for a set of the old Edelbrock valve covers and considered them a great find!

Factory and aftermarket four-barrel intakes are readily available on the used market, along with a number of vintage intake setups. The original 348 Tri-power setups aren't as expensive as you might think, if you keep your eyes peeled. An N.O.S. Offenhauser 4x2 intake sold recently on eBay for $305, but Offy still makes these in limited numbers, along with high-rise and low-rise dual-quads and triples. One of the biggest dealers in old and new Offenhauser equipment is Exeter Auto Supply (Exeter, California). If three or four carbs to tune just isn't enough for you, Offy has a six-carb setup, and Gear Drive Speed & Custom (Apple Valley, Minnesota) builds and sells four- and six-carb steel-tubing log intakes in kit form or fully welded, plus the company can make outside "lakes" headers, too.

Speaking of exhaust, the width of the W motors makes this a concern for '28-34 rods, where shorty tucked-in headers from Speedway Motors (Lincoln, Nebraska) or Sanderson Headers (South San Francisco, California) would work best. For '58-65 Chevys in which W motors resided, you can probably still find long-tube headers from manufacturers like Doug's Headers (San Dimas, California), or Stahl Headers (York, Pennsylvania). Jere Stahl got his start building headers for the Dave Strickler Z-11, which was tuned by Bill Jenkins in the days before he became a Chevy fan's demigod.

Several cam grinds can be obtained from COMP Cams (Memphis, Tennessee), and Crane Cams (Daytona Beach, Florida) has a retrofit hydraulic roller package.

You have plenty of choices in ignition system, as well. MSD Ignition (El Paso, Texas) has a billet distributor for the Ws, Mallory (Cleveland, Ohio) has a billet HEI distributor (may be too fat for dual-quad intakes), and Joe Hunt Magnetos (Rancho Cordova, California) has either classic racing magnetos or its high-energy distributors that are dead ringers for its mags and perfect for street/performance. Actually, a small-block Chevy distributor will work on these engines but has a longer distance from the clamping flange down to the gear. Some companies offer spacers to allow this swap, but experts tell us this may not be the right way to go. You could, of course, also rebuild your period-correct distributor and install a PerTronix kit to eliminate the points.

Some rodders with open engine compartments wouldn't think of using a vintage engine for their car unless there were some cool valve covers available for it, and they're in luck with the 348/409. Besides the old ones on the used market, Edelbrock has its finned and polished covers, as do Mooneyes (Santa Fe Springs, California) and Offenhauser, and PML (Inglewood, California) produces finned aluminum covers with Chevrolet in script in the middle. Who would put tin covers on a W motor with these choices, but chromed ones like some of the 409s had still have an appeal.

More than most engines you will read about in this vintage series, the W motors are no problem when it comes to transmissions. Many of the W motors came with three-speed sticks, and of course that bellhousing will accept T10 four-speeds and period three-speeds with overdrive, too. The automatic of the day was either the Turbo-Glide or Powerglide. Thankfully, the bellhousing bolt pattern on the back of the block is the same as a small-block Chevy, so all modern automatic transmissions like the TH350, TH400, and overdrive boxes will all bolt on, which is great news, because no expensive adapter or machine work is required.

Whole books have been written about these first "big-blocks" in Chevrolet history, and they have a formidable record in motorsports. Most of today's graybeard rodders can remember their teenage years, seeing the fullsize 348 and 409 cars battling it out at the drags with now-famous drivers speed-shifting down the 1320, and still have an appreciation for these motors. We've provided you with a peek into the street rod possibilities they offer, indicated some of the equipment now available for them, and if you were leaning toward a vintage engine for your next project, you might consider the W motor. This year is the 50th anniversary of the first 348, and that could be your sign that it's time to "eschew the crates" on moral grounds and build one of these!