Head Bolts
A-series head bolts are designed to be reused; they are not Torque-To-Yield (TTY) bolts.
Maintenance Schedule
Retighten cylinder head bolts every 24 months or 24000 miles whichever comes first, per the Periodical Maintenance and Lubrication Schedule.
1972 USA Owners manual (Page 32 ... 32):
[[1972#toc|
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24 months/24000 miles
600 mile service 24 months/24000 miles
See Changing Head Gasket for torque specifications and procedure.
Overview
BOLT-FIXING CYLINDER HEAD SHORT [9 needed, 97 mm length] * M10 x 97mm 11056-18001 36 lb ft [Original use: A10 & A12] 11056-H1000 43 lb ft [original use: A12] 11056-H2301 58 lb ft [original use: A12GX]
Note 'T' bolt for center of early A12 engine. The center bolt is thinner to allow oil to flow around it up to the rocker shaft.
BOLT-CYLINDER HEAD, TO OIL GALLERY [1 needed] 11057-18000 ' 11057-H1000 'T' 11057-H2300 '13' for 1967-1973 engines [97 mm length] 11057-H5700 '13' for 1974-up engines [111 mm length]
Bolts are the same for A10/A12/A14/A15, but:
- A14/A15 require the stronger bolts (marked '13')
- A14/A15 has one longer bolt (marked '13')
- redesigned A12 use the longer bolt (marked '12T')
A14/A15 long center bolt
- '12' bolts are the medium torque version, used on all A12 after about 1972. The 'T' center bolt matches, and is for the early A12. The longer 'T12' bolt is for the late A12 (mid-distributor version) and is the same length as the A14/A15 '13' center bolt
- the '13' bolts were designed for the B110 GX, but used for A14 and A15 afterwards. The center bolt is apparently marked '13', short for early A12, and long A14/A15.
Strengthened Cylinder Head Bolts
stronger bolts (marked '13')
1973 A12 (early engine, upgraded H1000 bolts) Torque: 40-43 ft-lb CENTER BOLT: 8 mm central portion (head marked 'T') OTHER BOLTS: 9 mm 
'12' bolts
Better to use the GX '13' center bolt, which is high-tensile chromoly V steel
"13" bolts were first used on the twin-carb A12GX Engine, as opposed to single-carb engine bolts. "13" bolts can be used with any early engine (they are simply stronger than the earliest bolts).
Note that A12/A12A/A13/A14/A15 all may use the '13' bolts, but the center bolt differs between early engines and late engines.
Center bolt 11057-H5000 and 11057-H5700 are interchangeable, but have different torque specs
'13' LONG center bolt 111mm length
http://datsun1200.com/uploads/photos/30677.jpg http://datsun1200.com/uploads/photos/30678.jpg
Part Numbers
Main: Head Part Numbers
Original Lo-torque bolts (B10 & early B110 -1172) - 36 ft-lb * 11056-18001 BOLT-FIXING CYLINDER HEAD SHORT * 11057-18000 BOLT-FIXING CYLINDER HEAD LONG * 11058-18000WASHER-LOCK FIXING CYLINDER HEAD
Newer medium torque bolts (1272-) - 43 ft-lb * 11056-H1000 BOLT-FIXING CYLINDER HEAD SHORT (9 needed) $2.90 * BOLT-FIXING CYLINDER HEAD LONG [Center bolt] $2.51 superseded by 11057-H5000/11057-H5010 * 11058-H1000 WASHER-LOCK FIXING CYLINDER HEAD $2.28
A12GX, A12T, A12S, A13, A14, A15, A12A - 58 ft-lbs * 11056-H2301 HEAD BOLT SHORT (9 needed) $3.96 Also used by Z16/Z18/Z20/Z22 (10 per engine) NOTE Some newer lo-power (round port) A12S are spec'd for 11056-H1000 * 11057-H2301 BOLT-CYLINDER HEAD LONG, TO OIL GALLERY (TO 6/73) $3.88 one needed * 11057-H5700 BOLT-CYLINDER HEAD LONG, TO OIL GALLERY (FROM 7/73) $4.03 one needed Also used by Z24, KA24E, NA20P (10 per engine) replaced 11057-H5000 (lo-torque version) * used by 1988- D21/WD21/C22 Z24 engine
A12: Long middle bolt marked 'T' (medium-torque)
A14: Long middle bolt marked '13' (hi-torque)
Hi-torque bolts marked "13" on the head. Remove the valve cover to verify.
head bolts Cro-Mo-V steel 13T
Lock Washer * 11058-H1000 WASHER-LOCK FIXING CYLINDER HEAD -8504 $2.28 * 11058-21002 Washer Cyl Head 8504- $2.57
1975 B210 JDM catalog C-260 11056-H1000 BOLT-cylinder head 9 A12S [single carb] 11056-H2301 BOLT-cylinder head 9 A12T [twin carb] 11057-H5000 BOLT-cylinder head 1 A12S [single carb] 11057-H5700 BOLT-cylinder head 1 A12T [twin carb]
1978 B210 JDM catalog C-402 BOLT-CYLINDER HEAD SHORT * 11056-H1000 9 A12S * 11056-H2301 9 A14 BOLT-CYLINDER HEAD LONG * 11057-H5000 1 A12S * 11057-H5700 1 A14
KA24E - 1989-1993 Nissan 240SX 11057-H5010 10 needed * Same as Datsun 1200 center bolt
KA24E - 1994-1998 Nissan 240SX 11056-F3F01 10 needed. TTY bolts, do not reuse * reportedly shorter than Datsun 1200/KA24E SOHC
Z20/Z22 Datsun 720 11056-H2301 10 needed * Same as Datsun 1200 (9 needed)
Z24 Datsun 720 11057-H5000 10 needed * Same as late Datsun 1200 (center bolt)
ARP Head Studs
Main: ARP#Cylinder_Head_Studs
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