Oldsmobile V8 Engines - Vintage Engines: Oldsmobile Rockets

Identifying Olds engines can be confusing, even for aficionados. The 303s are easy, as they are the only ones with round exhaust ports; all later engines have rectangular exhaust ports. There are enough variations over the years in deck height, stroke, manifolds, and cam and lifter specs that there is precious little interchange between the various engines, although in the Fifties a popular swap for the early engines was switching to a pair of '56 heads for better breathing. In the years '59 and '60, where both 371 and 394 engines were available, you can tell the 394s because they have three bolts on the center exhaust flange, 371's have only two. A "loose" guide to ID's are characters cast into the cylinder head at the center exhaust port. The '49-52 engines have no number, '53s have either a #3 or #5, '54-55 have a #8, '56s have a #10, '57-59 have #14, #15, or #16, and the '59-63 engines have numbers from #20 through #23. This gets you in the ballpark.

Once you get a useable long-block, rebuilding an Oldsmobile Rocket is as straightforward as any other engine. Accurate machine work in the bottom end, a good balance job (note that '58 and '59 371s are externally balanced), and a precise bore-and-hone job to work with modern moly rings will reward you with an engine that can outlive you. The Olds cylinder heads work great with a standard performance treatment of bowl cleanup, ports matched to the manifolds, and a three-angle valve job. As far as airflow is concerned, Olds heads have been flow-benched and the results were as good as the SBC "292" head, plus the Olds heads are already at 18 degrees.

There are Olds engine-builders like Dave Smith Engineering (Exeter, California) and Ross Racing Engines (Niles, Ohio) who specialize in stock and performance engines, and they can trick out your Olds to the limit of your wallet, with strokers, roller rockers (Ross), forged pistons, etc., but most of us with a lightweight traditional street rod don't really need the expensive extras to light up the wide whites. For a standard rebuild, Egge Machine (Santa Fe Springs, California), Kanter Auto (Boonton, New Jersey), Speedway Motors (Lincoln, Nebraska) and other companies (see Hemming Motor News) have complete rebuild kits with pistons, cam, lifters, bearings, and all the gaskets. Most of these companies offer upgrades, too, like including moly rings instead of OEM cast-iron. Speedway has a full page of Oldsmobile rebuild and other parts in their wish book. Cams are available from Iskenderian, Clay Smith, and others who made them then and now. Make sure you use a single-pattern profile, not a dual-pattern. Speed equipment for the Rockets is surprisingly easy to find at swap meets, although much of it is for the earlier engines. Intake manifolds abound, and Offenhauser still makes their 3x2 intake and low-rise dual-quads if you don't enjoy the hunting process.

Installing an Olds in your street rod is similar to the mounting of a Ford Y-block, in that they used a single front mount under the crank dampener and two side mounts off the bellhousing. You can use this arrangement if you like, but Hurst and other companies made mounts that bolted to the front of the engine and extended outward to meet their brackets at the frame rails. These are getting expensive now, but if you can build a street rod, making some simple side-mounts should be no problem. If you use a modern trans behind a Rocket, you can then use a simple, single mount at the rear. Modern bellhousings are available that have the mounting ears for a stock installation in an Olds. No one makes a basic tubular header for the early Olds motors, but that's fine with most rodders, who either build outside headers or use stock iron manifolds, which cling quite tightly to the block. The starter is on the left, on a removable cast-iron lower section of the engine's rear bell. This was a problem in rods using early Ford steering boxes, but was addressed in the old days with aftermarket aluminum lower bells that put the starter on the right. Finding one today isn't easy.

If there is any drawback to using an Olds engine in a street rod, it's the transmission choices. If you want a modern automatic transmission, so far the only choice is from Tanson (Sacramento, California). You send them a clean, empty case from a GM TH350, TH400, 700-R4, or 200-4R, and they will machine the front, weld on a new flange, and remachine it to fit the Olds. It's not inexpensive, and there is a wait, but it is a slick solution. Make sure your empty case has been thoroughly checked by a trans guy before you send it to Tanson.

For three-pedal guys, the situation is much better. Several companies make stick bellhousings, and Ross Racing Engines has new steel flywheels. Wilcap (San Luis Obispo, California) has an adapter set for the traditional swap of an Olds to an early Ford trans, plus a bellhousing and other parts to put most any GM stick transmission, 3-speed, four-speed, or even a T5, behind your Olds engine.

When it comes to bling for the Rockets, there's some out there in the vintage marketplace, and Offy (see Exeter Auto Supply) still makes their classic finned-aluminum valve covers. Similarly-finned valley covers are available from Eelco (see Streamline), O'Brien Truckers and Mooneyes. One note on aftermarket valley covers: if you're using an aftermarket intake it's no problem, but some OEM Olds four-barrel manifolds have a low underside section that will interfere with flat valley covers. Chroming your stock tin Olds valve covers is another great look, and if you can afford it, also chrome the front water crossover casting between the cylinder heads. Heck, dip anything removable in the tank!

The word rocket meant a lot in the '50s, implying speed and the latest in technology, and in looks, performance, reliability and character, those old Rocket Oldsmobile engines will make just as much of a statement in your next hot rod.