Stage I Off Center Block 4.1 Liter
Casting number 25500016

TOP

SIDE

Features of Note:
  • Notice the solid lifter valley with oil return being accomplished at the front (left) of the block through a hole where the valley and the front meet.
  • Notice the knock sensor provision ( hole on right side of picture)
  • This block is covered in cosmoline for protection. It's "virgin" and not rusted.
  • Notice 6 bolts per cylinder and studs
  • Deck is 0.500" thick
Features of Note:
  • Notice the "Power 6" cast into the side
  • Notice the casting number (upper left) 25500016
  • Notice the beefy casting in the skirts

BOTTOM

FRONT

Features of Note:
  • Notice thicker main webs in block
  • 2 bolt cast iron main caps
  • Stock location oil pump pickup
Features of Note:
  • Notice beefy front web near the mains
  • Ribs in the front valley area

Submitted by:

David Roland
david.roland@gm.com