stovebolt head bolt patterns

1929-1962
Chevrolet L-6 (straight/in-line 6) Overhead Valve Engines
the Stovebolt Six - the Cast-Iron Wonder
head-bolt patterns, torque settings

most of the information below was obtained from Shop Manuals
194, 181, and 207 photo was provided by Fred Nixon

1929-1962 Chevrolet L-6 (straight/in-line 6) Overhead Valve Engines the Stovebolt Six - the Cast-Iron Wonder `head-bolt patterns, torque settings` most of the information below was obtained from Shop Manuals 194, 181, and 207 photo was provided by Fred Nixon
First Generation 1929-1936 Low-Pressure Oil (internal lubrication) System
Year	Truck & Pass	*- head-bolt pattern*	Truck	*- head-bolt pattern*	Truck	*- head-bolt pattern*
1929	194 c.i.	above pattern
1930	194 c.i.	above pattern
1931	194 c.i.	above pattern
1932	194 c.i.	above pattern
1933	194 c.i.	above pattern
1934	194 c.i.	above pattern			207 c.i.	above pattern
1935	194 c.i.	above pattern	181 c.i.	above pattern	207 c.i.	above pattern
1936	194 c.i.	above pattern	181 c.i.	above pattern	207 c.i.	above pattern
pattern#1 Second Generation 1937-1953 Low-Pressure Oil (internal lubrication) System
Year	Truck & Pass	*- head-bolt pattern*	Truck	*- head-bolt pattern*	Pass	*- head-bolt pattern*
1937	216 c.i.	- pattern 1 (75-80 ft-lbs)
1938	216 c.i.	- pattern 1 (75-80 ft-lbs)
1939	216 c.i.	- pattern 1 (75-80 ft-lbs)
1940	216 c.i.	- pattern 1 (75-80 ft-lbs)
1941	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1942	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1943	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1944	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1945	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1946	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1947	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1948	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1949	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1950	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1951	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1952	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)
1953	216 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.	- pattern 1 (75-80 ft-lbs)	235 c.i.¹	- pattern 2 (90-95 ft-lbs)
note 1: The 1953 Powerglide-equipped passenger car engine was the first 235 engine with the high-pressure oil system. This engine used a head with the later bolt pattern (pattern 2). It used the earlier, 2-bolt valve cover and had the short side cover, same as the 1950-1953 235 truck and 1954-1962 235/261 side covers (it did not cover the spark plugs).
pattern #2 pattern #3² Third Generation 1954-1962² High-Pressure Oil System (internal lubrication)
Year	Pass	*- head-bolt pattern*	Truck	*- head-bolt pattern*	Truck	*- head-bolt pattern*
1954	235 c.i.	- pattern 2 (90-95 ft-lbs)	235 c.i.	- pattern 2 (90-95 ft-lbs)	261 c.i.	- pattern 3 (90-95 ft-lbs)
1955	235 c.i.	- pattern 2 (90-95 ft-lbs)	235 c.i.	- pattern 2 (90-95 ft-lbs)	261 c.i.	- pattern 3 (90-95 ft-lbs)
1956	235 c.i.	- pattern 2 (90-95 ft-lbs)	235 c.i.	- pattern 2 (90-95 ft-lbs)	261 c.i.	- pattern 3 (90-95 ft-lbs)
1957	235 c.i.	- pattern 2 (90-95 ft-lbs)	235 c.i.	- pattern 2 (90-95 ft-lbs)	261 c.i.	- pattern 3 (90-95 ft-lbs)
1958	235 c.i.	- pattern 2 (90-95 ft-lbs)	235 c.i.	- pattern 2 (90-95 ft-lbs)	261 c.i.	- pattern 3 (90-95 ft-lbs)
1959	235 c.i.	- pattern 2 (90-95 ft-lbs)	235 c.i.	- pattern 2 (90-95 ft-lbs)	261 c.i.	- pattern 3 (90-95 ft-lbs)
1960	235 c.i.	- pattern 2 (90-95 ft-lbs)	235 c.i.	- pattern 2 (90-95 ft-lbs)	261 c.i.	- pattern 3 (90-95 ft-lbs)
1961	235 c.i.	- pattern 2 (90-95 ft-lbs)	235 c.i.	- pattern 2 (90-95 ft-lbs)	261 c.i.	- pattern 3 (90-95 ft-lbs)
1962	235 c.i.	- pattern 2 (90-95 ft-lbs)	235 c.i.	- pattern 2 (90-95 ft-lbs)	261 c.i.	- pattern 3 (90-95 ft-lbs)
note 2: There is a special drilled bolt that is used when a 1959-62 block is used with an earlier head and the 59-62 rocker arm assembly, to reduce the oil flow to the rockers. This bolt is used with the drilled-bolt Plug # 37 64 579 that is installed in the block oil-port near the right center head bolt. This plug blocks the original oil path and sends it through the drilled head bolt (posted by Pre '68 Dave, on The Stovebolt Page forums). note 3: The design of the lifters changed in 1958, due to a new oiling path from both ends of the camshaft into/through the lifter jourbals. Itr is imperative that these new lifter (that have a annular ring) be used in the 1958-1962 blocks. note 4: The 54-62 235 and 261 c.i. heads had the same bolt pattern, but the Inliners International Tech Tip on head-bolts states that the tightening sequences are different. note 5: The 261 c.i. head has extra coolant holes between cylinder-pairs; these holes may be drilled into the 1954-1962 235 heads, for use on a 261 c.i. block (the photo below is from the Jim Carter Antique Truck Parts, Tech Article on the 261 c.i. engine).