Buick Nailhead Engine Build: Step-by-Step Guide

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Near the tip-top of the list of well-dressed vintage hot rod engines that never fail to elicit a bitchin’ remark from admirers are the Buick nailheads. Those upright valve covers can be spotted from a mile away, and they just look so right decked out in finned aluminum. We have to admit, it’s one of the reasons we wanted to build one.

But besides their good looks, what’s so great about nailheads? The first nailheads of ’53 to ’56 came in two sizes: 264 ci in the entry level cars and the much more powerful 322-incher usually reserved for the upper-end models. To help make up for puny, nail-like valves (get it?) and a prohibitively restrictive head design, nailheads employed camshafts with higher than average lift and longer duration. That pairing actually made for superb low-end torque, which is exactly what Buick had in mind. You gotta remember, the Fireball 8s were never designed to be hot rod or performance engines, they were designed to be smooth-running, torque-making workhorses to pull around 2-1/2-ton luxury Buicks.

Gobs of torque gets cars moving off the line, so that along with small packaging that allowed them to easily slip into A’s and Deuces with or without hood sides made them instantly desirable swaps. Out on the streets and strips, nailheads quickly developed a reputation for being exceptionally hard to kill thanks to stout forged cranks and rods that could take repeated thrashings. Nailhead hero Max Balchowsky used near stockers to beat up on Maseratis and Ferraris on road courses with his homebuilt Old Yeller II, and Tommy Ivo was sitting behind two when he drove the first gas dragster to break the 9-second barrier with an 8.69 pass. Even Tony Nancy’s famous 22JR roadster ran an injected nailhead.

Editor’s note: This story was originally published in the November 2009 issue of HOT ROD Deluxe magazine.

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Test Subject: 322 Buick Nailhead Engine

The test subject for this story is a 322 from a ’54 Roadmaster that, despite 55 years and who knows how many miles, still ran quite well when we pulled it from the car. The Series 70 Roadmaster engine originally boasted the highest compression in the ’54 lineup at 8.5:1. That, coupled with the unique Stromberg four-barrel, helped deliver a rating of 200 hp and 309 lb-ft on the old SAE gross scale—strong numbers in those days.

To get an idea of where to start, we called noted nailhead guru Russ Martin of Centerville Auto Repair to get some parts-swapping tips. According to Martin, our ’54 has a good billet steel cam and the benefit of a factory windage tray, but several key parts were holding it back. To go to the next level we needed bits from a ’56: the heads, rods, and exhaust manifolds. The ’56 redesigns of those parts plus a compression bump to 9.5:1 were responsible for bringing the ’56 322’s rating up to 255 hp and 341 lb-ft. But, according to Martin, there’s much more available with a good induction system and a little cam tweaking.

Related: History of the Buick Nailhead

Junkyard Donor Engine

So this is actually a tale of two engines. To build our hot rod 322 we’re going to combine the best elements of our old ’54 and a core ’56 engine to build a solid performer. Armed with a bit of a plan and two 322s, we headed to Max Herman Sr. at H&H Automotive to help us map out the logistics. Though H&H is renowned for its flathead Fords and A, B, C, and T bangers, Herman heads up the lesser known Vintage Hot Rod Engines division that’s geared toward hopping up just about any antique American iron ever produced. With 40-plus years of engine building under his belt, there aren’t many engines he hasn’t built—but even he hasn’t built a nailhead like this one. We concocted a unique recipe including new and never-before-seen parts for this engine, and after some late nights at H&H, we ended up with a bitchin’ looking hot rod 322 that makes 325 hp and 385 lb-ft.

Revised Pent-Roof Combustion Chamber

It’s difficult to see the revised pent-roof combustion chamber on the ’56 head (right), but the larger tulip exhaust valve that helped increase exhaust scavenging versus the flat ’54 is readily apparent. The ’56 uses 1-3⁄8-inch valves compared with the earlier ones at 1-1⁄4. Quench pads were added in ’54, though chamber sizes, piston heads, and head gasket compressed thicknesses varied throughout the run of ’53 to ’56 nailheads, so compression ratio must always be checked when mixing and matching parts.

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Larger Drain Holes

On the top, we find another benefit to the ’56 heads (right): larger drain holes that help drain oil back more quickly.

Measuring Chamber Volume

Since our goal is 10.0:1 compression, we measured the chamber volume of the ’56 heads as part of our equation to calculate how much material needed to be removed during surfacing and found them at 117 cc.

Wall of Casting Flash

Nailheads are notorious for poor flow, especially 264s and 322s, and here’s one of the reasons: This great wall of casting flash (arrow) was almost 1⁄8 inch tall, and every runner was full of similar ones.

Mild Port Job

Herman performed an excellent mild port job, clearing out the flash and smoothing and blending the entry. He also opened up the intake and exhaust ports and matched them to our Best Gasket kit from Egge Machine. There’s no point in getting much more aggressive than that with a street nailhead.

Upgrading Springs

Nailheads use a dual valve­spring system from the factory. As part of our upgrade, we’ll be swapping in the longer and stronger 401 springs from Egge for a little bump in spring rate. Our original springs tested at 58 pounds installed and 155 open, the 401 springs were 85 installed and 205 open. The spring installed height is 1.55 inches.

Valve Job

The valve job included a three-angle cut using 60, 45, and 30 degrees on the stock valves that came from the ’56 heads. Upgrading to hardened valve seats isn’t necessary in nailheads, which is good because material is thin and coolant passages are very close by, making the odds of cracking the heads during cutting pretty good.

Please Send Crimping Pliers

When we made our own bands, we figured we’d just hold them in place and bend them. No-go. We had to put the first bend in off the frame and then clamp them in place. We’re sure the original manufacturer had ratcheting crimping pliers or something similar.

Decking the ’54 Engine Block

The left bank of our ’54 block turned out to be slightly off square (not perpendicular to the mains), which is more common than you might think on vintage engines. Herman bored everything square then took care of some significant high and low spots on the deck. After decking, the pistons sat 0.025 below deck.

A Performance Regrind on the ’54 Block

There are blank billets floating around out there for nailheads, but good luck finding one. Our cast-iron ’56 cam was wasted, but the billet steel ’54 was in pretty good shape, so we sent it out to vintage cam guru Joey Bray at American Custom Cam for a performance regrind with 276 degrees of advertised duration, 224 degrees of duration at 0.050-inch tappet lift, 0.430-inch valve lift (with 1.5:1 rockers), and a 110-degree lobe-separation angle.

Nailhead Engine Balancing

Since we were pairing our ’56 crank with a ’54 flexplate and a rebuilt damper from Damper Dudes, we sent the assembly to B&T Performance Engine Balancing to make sure everything was harmonious. Good thing too because according to Bill Mizia at B & T we were pretty far off, which is very common on vintage engines. The nailheads are externally balanced at the factory, and we did not convert ours to internal balancing.

Upgrading Rods on Early 322s

Besides being a much stronger forging, here’s the main reason for upgrading rods on early 322s. The ’54 rod (right) is an archaic clinch-pin style that pairs unpredictably with hot rodding and higher power levels. The ’56 rod allowed us to use modern-style, 0.940-inch press pins from Egge.

Off-the-Shelf Forged 322 Pistons

Using a sample piston from our ’56 engine, Ross Racing cut these forged slugs with old-school 5⁄64, 5⁄64, 3⁄16 ring grooves. Thanks to Ross and HRD, these are the first off-the-shelf forged 322 pistons available—ask for Job No. 123795. Since our 322 has the same bore size as a 350 Chevy bored 0.030 over, our Total Seal gapless ring pack is a standard stocking item as well. With 45cc domes on the pistons and 0.013-inch head gaskets, the final compression ratio is 9.97:1.

Related: Cast vs. Forged Pistons and All About Pushrod Design

Timing Chains: Count the Clicks

All 322s in Buicks used the old Morse link-style timing chains, but those that landed in heavy-duty Chevy trucks between ’56 and ’59 used a modern-style double roller chain. Centerville often has N.O.S. Borg­Warner kits like this one around. Pay attention though; rather than lining up the dots, you count the links between them. The old chain will be 12 links, the new one is 16.

Aluminum Water Pump Cover

The ’56 water pump is a revised and more efficient design than the ’54, but unfortunately the front cover from our parts engine was heavily rusted and pinholed—a common problem on neglected nailheads. Fortunately for us, Rocking B Enterprises just released its killer new aluminum cover for 322-425ci nailheads. Note the cast-in timing tab.

N.O.S. Nailhead Water Pump

​​N.O.S. early nailhead water pumps are hard to come by, but Egge is one of the few shops out there that offers a full rebuild service with upgraded shaft and bushings for just about any water pump out there. All pumps are checked before shipping. As Bob Egge told us, “If it’ll hold vacuum, it’ll pump water.”

Upgraded Rope Seals

We’ve found the new graphite-impregnated-style rope seals made by Best Gasket seal great (and are often the only good option), but modern-style neoprene lip seals can also work in nailheads and Centerville Auto has ’em. Our bearings are 0.010-under Clevites from Egge. Note that the mains have their respective numbers cast into the tops making it easy to replace them in the correct order.

Oil Pickups: ’56 Is the Preferred Style

Though the oil pickups are very different, the ’54 and ’56 pumps are actually identical. The ’56 pickup is the preferred style to use. Unless there’s been water in the pan or catastrophic oil pump failure, this simple rebuild kit from Egge is all that’s needed to restore function.

Catalog Buick Green Paint

​​Like our correct Buick green paint? Bill Hirsch Auto has a huge catalog of vintage paint colors that should inspire you to put down the red and black rattle cans. Here you can also clearly see the ’54 windage tray. The massive freeze plugs are stocking items at Centerville Auto.

Related: How to Paint an Engine Block

Don’t Forget the Oil Gallery Plug

See that oil gallery plug on the right inside the block? It’s an easy one to forget, but vital for oil pressure. Centerville Auto keeps plugs of the correct length and diameter in stock, as well as the occasionally forgotten but critical snap ring that holds the cam in place.

’54 Head Gasket: It’s a Secret

The 0.045-inch-thick, multilayer head gasket is the common replacement provided for nailheads and correct for many models, but our ’54 Roadmaster engine originally came with 0.015-inch steel shims, which was the secret to their compression and power bump. Centerville Auto was our source for these hard to find head gaskets.

Rebuild Valvetrains

All nailheads have identical valvetrains, so rather than rebuild the stock, cast-iron, 1.5:1 rockers from the 322, we procured a set of lightweight 401 aluminum 1.6:1 rockers and sent them to Rocker Arm Specialist for a complete rebuild and an upgrade to adjustability to help us dial in the valvetrain.

Regrind and Adjust

Though our ’54 cam was in pretty good condition, American Cams regrinds each lobe to be perfect, which can result in inconsistent pushrod length requirements. Note the varying measured lengths written on the head. No problem a set of Smith Bros. adjustable pushrods paired with our adjustable rocker arms can’t fix. The translucent red goo is our Torco assembly lube from Egge.

Weber Carb Intake

Here’s the coolest part of our build: the Weber carb intake from Kring Buick/Milr Products. Don Kring and Dan Brown are two nailhead lovers who create some of the nicest castings we’ve ever come across. Considering the questionable flow on some vintage nailhead intakes, this may be one of the best options ever made for them. Since there’s no crossover, this intake works with all 264-425ci nailheads, regardless of deck height.

Mounting the Spark Plug Covers

The striking new Kring rocker and spark plug covers required longer-than-stock mounting bolts. We used a piece of all-thread for the rocker covers and a stud made from a 41⁄2-inch bolt to mount the spark plug covers. The spark plug cover stud goes into a water jacket, so make sure it’s sealed well.

Direct Bolt-On Nailhead Housing

Early nailheads used a canister-style oil filter that’s infuriating and messy to change and questionably effective at filtering. Adapters are available for the original housing to upgrade to modern spin-on-style filters, but we opted to pick up a ’59 to ’60 364 nailhead housing that uses a spin-on filter and is a direct bolt-on; it’s from Centerville Auto.

Recasting the New Weber 48 IDA-Style Carbs

Atop our Kring intake we’re running Empi’s (yeah, the VW guys) new Weber 48 IDA-style carbs. Working with permission from Weber, Empi has recast the carbs with a few internal tricks that make them easier to keep in tune, and they often make more power than original Webers.

Custom Block

​​Rather than attempt to find a fuel block that would fit, Herman whittled out this custom block from a solid piece of aluminum and glass-beaded it to match the finish of our cast Kring parts. These aren’t for sale separately; Herman just makes them for H&H projects when necessary.

Distributor Rebuild

Russ Martin rebuilt our ’54 distributor and set it up for mechanical advance only since our Empi carbs don’t provide an easy way to get a good vacuum signal. Rather than deal with points, we upgraded to an Ignitor electronic ignition from PerTronix. The slick stainless distributor clamp is another cool new nailhead part from Rocking B.

Choosing the Right Air Horns

Empi has two styles of air horns available: these beautiful bells and a more vertical style similar to those found on Shelbys. Big thanks to Don Kring for setting up the somewhat complex linkage for us on the carbs. If you order a complete package with carbs through Kring, he’ll do the same for you.

Restoring the 322’s Rusty Manifolds

Unless you can run lakes-style headers or are ready to weld up your own, stock ’56 manifolds are the best bet for 322s, as they offer much better flow than earlier manifolds. Though the spacing is the same, later manifolds or headers for 364 to 425 nailheads won’t work due to a difference in port shape. Xtreme Performance Heat Coatings restored our rusty manifolds and applied a coating that nicely matches our aluminum parts.

Balancing Air and Fuel Flow

Since we’re newbies to Weber-style carbs, tuning expert and all-around accomplished racer Wyatt Radke from Empi took time to swing by Dyno-Motive to help us balance the air and fuel flow. A few main and idle jet and air bleed swaps later we got the air/fuel ratio in the 12.5 range, and after a 20-minute break-in with Torco break-in oil, we adjusted it down to an 850-rpm idle.

Rebuilt Buick Nailhead V-8 Hits the Dyno

After discovering it preferred 36 degrees of total timing paired with 55 idle jets, 155 main jets, and 200 air bleeds, we were rewarded with a very respectable 325 hp at 5,000 rpm and an even better plateau-like torque curve that peaked at 385 lb-ft at 3,800 rpm and averaged 357 lb-ft from 3,000 to 5,500 rpm. Not bad for a little antique engine.

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