Buick Engine Torque Specifications

The following torques and torque patterns were compiled with the help of Todd.

I was finally able to go through all the shop manuals from 53 to 67. In all cases, the left head is the same part as the right head, except for maybe a water jacket plug that has to be reversed depending on L or R side usage. Pre-tightening is done by going around the bolt sequence three times, gradually increasing the torque on each round. Post-tightening is specified for most engines, where the bolts are to be torqued again to the final value after the engine is up to full operating temperature. Perfect Seal sealing compound (Buick part #980456) is specified for use on the bolts in some cases. This would be where ever the bolt hole in the block goes through to the water jacket. There are probably some minor errors in the shop manuals which appear in the following specs. Some years showed different torque ranges in the same shop manual. There is some confusion as well when the number of bolts were reduced in the smaller engine sizes. These are things I couldn't prove out by going to parts lists, photos, or other books. Todd

Engine Torque Specifications

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Buick Straight Eight

MODEL	CYLINDER HEAD	ROD BEARINGS	MAIN BEARINGS	CRANKSHAFT BALANCER	FLYWHEEL	MANIFOLD	REFERENCE
263/320	65 - 75	263 40-45 320 60-65	90-100	100-110	sync. 35-40 dyna. 50-55	25-30	1951 shop manual

Head bolts on the 263 as the head bolts are bottomed out and don't go into the water jacket. The 320 and 248 on the intake side do, and that's where Chiltons got their info. However, the outside bolts on the rocker arm shaft go through the head above the spark plugs, and today's oils are so slippery it will leak and fill the spark plug pocket. Permetex #3 will seal the threads nicely, and the head bolts on 320's and 248's, and it should be done as I've had coolant sneak through the threads and into the oil. alleycat

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Torqueing the Nailhead

MODEL	CYLINDER HEAD	ROD BEARINGS	MAIN BEARINGS	CRANKSHAFT BALANCER	FLYWHEEL	INTAKE MANIFOLD	EXHAUST MANIFOLD	REFERENCE
264/322/364	65 - 75	40 - 45 3/8-24 140 - 160	50 - 60	25 - 30	10 - 15	1957 shop manual
401/425	65 - 75	30 - 35 11/32-24	50-55 rear 65-70	140 - 160	50 - 60	25 - 30	10 - 15	1963 shop manual

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215 V8

Torque was 50-55 for the 61 and 62 models. The 63 model required 65-75. There was a Buick service letter put out many years later which raised the values on the earliest years of the 215. All years had 14 bolts. Post-torqueing is not specified. Perfect Seal is specified for all years. The tightening order is the same as the late model nailheads.

198 V6

In 1962 and 1963, 65-70 is the given torque value. These engines had 11 bolts per head. Post-torqueing is not specified. Use of Perfect Seal is specified.

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225 V6

The 1964 and 1965 225 V6 use a torque value of 65-70. They had 11 head bolts and used the same pattern as the 198 (above). In 1965 The Torque was increased to 70-75. In 1966 the head went to 8 bolts, the torque continued to be 70-75. In 1967 the torque specification was changed to 65-80 and retorqueing was specified.

MODEL	CYLINDER HEAD	ROD BEARINGS	MAIN BEARINGS	CRANKSHAFT BALANCER	FLYWHEEL	INTAKE MANIFOLD	EXHAUST MANIFOLD
1967 V6 225	65 - 80	30 - 40	95 - 120	140 - 160	50 - 65	45 - 55	15 - 20

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300, 340, 350 V8

In 1964 the 300 shows 14 bolts and used a torque of 65-70. It used the late model nailhead torque pattern (shown above). Post torqueing is not specified, Perfect Seal is.

In 1965 the 300 shows 10 bolts and increases the torque to 70-75.

In 1966 torque goes to 65-80 and in 1967 post torqueing is specified.

It would be recommended to be at the upper limit for the 350.

MODEL	CYLINDER HEAD	ROD BEARINGS	MAIN BEARINGS	CRANKSHAFT BALANCER	FLYWHEEL	INTAKE MANIFOLD	EXHAUST MANIFOLD
1967 V8 300, 340, 350	65 - 80	30 - 40	95-120	140 - 160	50 - 65	45 - 55	15 - 20

More 300/340 specs here

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MODEL	CYLINDER HEAD	ROD BEARINGS	MAIN BEARINGS	CRANKSHAFT BALANCER	FLYWHEEL	INTAKE MANIFOLD	EXHAUST MANIFOLD
1967 V8 400, 430, 455	100 - 120	45 - 50	80 - 115	200+	50 - 65	45 - 55	15 - 20