I have replaced several ls1 heads on older cars and was wondering on the newer ls1's, the 2004's to be exact, have shorter head bolts than the older ones. Are the torque specs still the same? Why did they go to shorter head bolts? Thanks for the help.

 

First design engine blocks (97-03) have different drill and tap depths using both medium length 100 mm (3.94 in) and long 155 mm (6.1 in) M11 cylinder head bolts. Second design engine blocks (2004) use only the medium length 100 mm (3.94 in) bolt with a common drill and tap depth. The torque sequence is the same while the procedure is as follows (included the older and newer for comparison).

Old Design
1] Tighten the first design M11 cylinder head bolts a first pass in sequence to 30 N·m (22 lb ft).
2] Tighten the first design M11 cylinder head bolts a second pass in sequence to 90 degrees using the J 45059 .
3] Tighten the first design M11 cylinder head bolts (1, 2, 3, 4, 5, 6, 7, 8) to 90 degrees and the M11 cylinder head bolts (9 and 10) to 50 degrees a final pass in sequence to using the J 45059 .
4] Tighten the M8 cylinder head bolts (11, 12, 13, 14, 15) to 30 N·m (22 lb ft). Begin with the center bolt (11) and alternating side-to-side, work outward tightening all of the bolts.

New Design
1] Tighten the second design M11 cylinder head bolts (1-10) a first pass in sequence to 30 N·m (22 lb ft).
2] Tighten the second design M11 cylinder head bolts (1-10) a second pass in sequence to 90 degrees using the J 45059 .
Tighten the second design M11 cylinder head bolts (1-10) a final pass in sequence to 70 degrees using the J 45059 .
3] Tighten the M8 cylinder head bolts (11, 12, 13, 14, 15) to 30 N·m (22 lb ft). Begin with the center bolt (11) and alternating side-to-side, work outward tightening all of the bolts.