Thread: 364 nailhead

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Some info I found while surfing.......

Buick nailhead engines were built from 1953 to 1966. They have a distributor in the rear, a starter on the left, and the valve covers face straight up. Displacements changed from year to year, and are as follows: 264, 322, 364, 401, and 425 ci.

Interchangeable Parts From Other Engines

V-6 Buick neoprene rear seals

400-455 Buick front seals

V-6 cam bumper (threaded type)

350 Buick main stud kits

400-455 Buick rod bolts and nuts

400-455 Buick rod bearings

400-455 Buick valve locks

400-455 Buick ring gear ('57-'66 only)

Engines from 1953 should be avoided--they have no harmonic balancers, bad combustion chambers, and heavy pistons.

Top Nine Assembly Mistakes

1. The flywheel is on wrong. It will fit six ways, and you must line up the guide hole.

2. The front cam bearing is not installed properly.

3. The balancer bolt is not tight enough. This allows the balancer to move on the crank, which will ruin the crank and break the balancer.

4. Improperly ported heads stick to the bowl work only.

5. Ruining heads while installing valve seats--it's easy to hit the water jackets on many heads.

6. The oil pump shaft binds. Install the distributor first, then file out holes in the pump body until it fits.

7. Mixing pushrods with 5/16- and 3/8-inch tips. Aftermarket lifters and pushrods sometimes have 5/16-inch tips.

8. Spinning the water pump too fast. Cars with A/C are overdriven 1.4, cars without are underdriven 0.9. Around 1.0, freeway temperatures drop 10 to 20 degrees at 65 mph. Also, airless water pumps have three impellers, while A/C pumps have five. Three seem to work better most of the time.

9. Oversize valvespring pockets--this puts the spring in the pushrod hole and quickly chews up the pushrod.

Camshafts

The '53-'56 camshafts are interchangeable. They are steel and have smaller bearing journals, while '57-'66 camshafts are cast-iron with large journals. These can be ground down to fit the early engines.

The stock cam is a 270 grind and will rev to 5,500 rpm. Don't waste money on mild-horsepower cams--they ought to be 214 degrees at 0.050 minimum. The 401 had a 114-degree centerline, and the 425 had a 109 centerline. Use 114 for big cams and 109 for tamer ones. Stock Buick billets can be ground down to 7/8 inch if necessary.

Valvesprings

Stock back-cut valves are fine, but it's best to install 1.94-inch intakes. Tests have shown no increase in horsepower with larger exhaust valves. Chevy 1.5 and 1.94 valves, springs, and retainers can be used, but aren't easy to install.

Oil Pump

Most of the time, 40-45 pounds of oil pressure is plenty. If you are going to turn high rpms (in road racing for instance), find a '61 pump--it's the best for late engines.

Oil Pans

Rear sump pans from '57-'66 and '65-'66 GS Skylarks fit all '57-'66 engines. The '53-'56 engines all had rear sumps, but will not interchange with later nailheads.

Intakes

Top performance seems to come from factory cast-iron single and dual-quad intake manifolds. Aftermarket aluminum dual-quads, like Offenhauser or Edelbrock intakes, also work and weigh less.

Carburetors

Carter and Edelbrock AFBs work well on Buicks. The 500-cfm is best for 322ci engines, the 600-cfm for 364ci, and the 750-cfm for 401-425ci engines. The dual-quad intakes can use 600- or 750-cfm carbs for 401-425s. Nailhead engines like big carbs, unlike most other engines. A big-cam 425 will run great with two 750-cfm carbs on a dual-quad intake.

Distributors

Stock distributors are hard to beat. The '53-'63 models are the best in stock condition--the advance curve is fine, the same as '64-'66 dual-quad engines. Stock cam engines should have about 12 degrees initial, 30 degrees total at 2,000 rpm. Performance cams should have 12-15 degrees initial, 32-35 degrees total. These specifications don't include vacuum advance, but most stock vacuum advances work fine. All distributor parts from a Chevy are the same. Shim the distributor shaft if it's worn.

Connecting Rods

All nailhead rods are forged and very strong. There are three different lengths depending on cubic inches. Pontiac rods can be used. They are longer and make more power, but they require machining and custom pistons to make them fit in the engine.

Rocker Arms

All nailhead rockers are interchangeable. The '53-'58s are iron 1.5:1 ratio, the '59s are 1.6:1 ratio, and the '60-'66s are aluminum 1.6:1 ratio. The later-model ones are the best for stock and mild engines. The iron is stronger and can be used when necessary. All the rockers are very short and should put a lot of back-and-forth pressure on valves and guides. High-lift cams need bronze guides installed. The best stock guides to use are '66s, which are cut for P.C. seals.

Heads

Heads from 1953 to 1956 have round exhaust ports and smaller valves than '57-and-ups, and these shouldn't be interchanged. The factory made experimental aluminum heads with stock ports, and in 1962 cast "D" port heads which had 1/2-inch taller exhaust ports. These were good for 15 hp with cast-iron manifolds.

Cranks

All Buick cranks are forged. Cranks are as follows: '54-'56 are the same; '57-'61 are the same and yield 364 ci; '59-'63 are the same and yield 401-425 ci; '64-'66 are the same and yield 401-425 ci, but the back of the crank is different, so it can be used with a Turbo 400 transmission.

Transmissions

The Dynaflow was used behind all '53-'63 cars with different types depending on the year of the car. The Turbo 400 can be used with any '64-'66 engine, but stay away from the '64. The '65 and '66 Skylark GS used a two-speed 300 transmission. Manual transmissions were also available and work fine, but '57-'66 engines can be mated with the '65-'66 Turbo 400, and it makes an unbeatable combo--especially with the 300 converter switch-pitch setup.

Exhaust Manifolds

The '53-'56 manifolds have round ports, and the '57-'66 manifolds have rectangular ports. Manifolds should not be swapped. The '61 manifold is a good choice for later-model engines if headers are not used.

Miscellaneous Buick Information

A spin-on oil filter housing from a '59-'60 engine will bolt on a '57-'58 engine.

Hard seats aren't mandatory because the valvetrain is lightweight, and the valves are small and don't need stiff valvesprings (260 open pressure maximum).

How to identify a nailhead at a glance (check ID number for exact year): 264-322ci--The '54-'56 has a bigger bellhousing, three-bolt engine mounts, round exhaust ports, and measures 81/4 inches across the intake manifold bolts. 364ci--The '57-'61 measures 83/4 inches across the intake manifold bolts and has four-bolt engine mounts and rectangular exhaust ports. 401-425ci--The '59-'66 measures 9 inches across the intake manifold bolts and has four-bolt engine mounts.

The only parts that interchange from the first nailhead to the last are: distributors, rockers and shafts, valve covers, aftermarket valley covers, rod bearings, rod bolts and nuts, valvesprings, locks, retainers, and guides.

Tech Thanks for all that info. Nailheads are sharp looking engines. Just never worked on one myself. Looks like I'll be doing some work this summer on one.