Stage II Off Center Block 4.1 Liter
Casting number 25500017



86-87 Production Block Top View
86-87 Production Block Bottom View
Features of Note:
  • Late Stage II off center block cast in 1994 as a special run of about 50 blocks for Buick Motorsports.
  • Notice the solid lifter valley with NO oil return holes. Oil is returned on the ends of the block valley with the areas covered with the yellow epoxy and a screen.
  • Notice the HUGE intake ports on the aluminum Stage II heads on this particular block
  • It's kind of hard to see, but this block has provisions for 6 bolt holes per cylinder
  • The tower usually found in the front of the block has been milled off and plugged so a turbo drain back line can be plumbed like the production block
Features of Note:
  • Four bolt mains
  • Thicker pan oil pan rails than production block
  • This particular block was cast without an oil pump pick up and designed to be used as a dry sump only.
    Ruggles however, machined a pickup from a broken Stage II and fitted it to this block. The engine uses an external pickup now so the original is blocked with epoxy and an expansion plug.
  • Note all 4 billet caps indicating the the block was cast later than '85 meaning it takes a rear main oil seal from a BBChevy. Blocks cast prior to 1985 had a cast cap in the front and rear and use a stock type Buick seal.
  • This particular engine is pictured with Carillo rods and forged crank, it has made over 1100hp and has remained dimensionally sound through 3 freshen jobs.

Submitted by:

Bill Anderson