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The following torques and torque patterns were compliled 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 whereever the bolt hole in the block goes through to the waterjacket.
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
Buick Straight Eight
MODEL CYLINDER
HEADROD
BEARINGSMAIN
BEARINGSCRANKSHAFT
BALANCERFLYWHEEL MANIFOLD REFERENCE 263/320 65 - 75 263 40-45
320 60-6590-100 100-110 sync. 35-40
dyna. 50-5525-30 1951
shop manual
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Torqueing the Nailhead
MODEL CYLINDER
HEADROD
BEARINGSMAIN
BEARINGSCRANKSHAFT
BALANCERFLYWHEEL INTAKE
MANIFOLDEXHAUST MANIFOLD REFERENCE 264/322/364 65 - 75 40 - 45
3/8-2450-55
rear 65-70140 - 160 50 - 60 25 - 30 10 - 15 1957
shop manual401/425 65 - 75 30 - 35
11/32-2450-55
rear 65-70140 - 160 50 - 60 25 - 30 10 - 15 1963
shop manual
1953 - 1961
1962 - 1966
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 rasied the values on the earliest years of the 215. All years had 14 bolts. Post-torqueing is not specified. Perfect Seal is specifed 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.
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
HEADROD
BEARINGSMAIN
BEARINGSCRANKSHAFT
BALANCERFLYWHEEL INTAKE
MANIFOLDEXHAUST MANIFOLD 1967
V6 22565 - 80 30 - 40 95 - 120 140 - 160 50 - 65 45 - 55 15 - 20
300, 340 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.
MODEL CYLINDER
HEADROD
BEARINGSMAIN
BEARINGSCRANKSHAFT
BALANCERFLYWHEEL INTAKE
MANIFOLDEXHAUST MANIFOLD 1967 V8
300, 34065 - 80 30 - 40 95-120 140 - 160 50 - 65 45 - 55 15 - 20
More 300/340 specs here
Buick 300 - 340
MODEL CYLINDER
HEADROD
BEARINGSMAIN
BEARINGSCRANKSHAFT
BALANCERFLYWHEEL INTAKE
MANIFOLDEXHAUST MANIFOLD 1967 V8
400, 430100 - 120 45 - 50 80 - 115 200+ 50 - 65 45 - 55 15 - 20
Buick 400 - 430
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