Product Summary

265, 305, 3.750" Bore Size, Siamese Cylinder Wall

  • Engineered to accept OEM roller rockers and cams
  • The decks are parallel within .002" and has 350 main journals
  • Block is cast from high nickel iron and has a priority main oiling system
  • Designed for high-performance and heavy-duty applications producing up to 600 horsepower
  • The ideal starting point for hot rodders, drag racers, circle track competitors, off-roaders, and high-performance marine enthusiasts

Key Specs

MFG. Part #31161411

Need To Know

Truck Ship

Truck shipments must be pre-paid with a credit card, certified check or money order

Quick and Easy Returns

Return Policy


Designed for high performance and medium duty applications, the SHP (Special High Performance) block is the ideal starting point for hot rodders, drag racers, circle track competitors, off-roaders, and high performance marine enthusiasts.

Don't waste your valuable time sourcing, cleaning, machining and prepping a 40 year old core when you can have a brand new precision machined block with all the most desirable features for just a few dollars more.


  • Priority main oiling system.
  • Siamese cylinder bores with extra thick walls.
  • Optional full water jacketed non-siamese cylinder bores.
  • Extra thick decks ensure reliable head gasket seal.
  • Blind head bolt holes don’t go through to water jacket.
  • Scalloped water jacket walls improve flow around cylinders for better cooling.
  • Clearance for 3.750" stroke with steel rods.
  • Splayed outer bolts on middle main bearing caps.
  • Non-siamese water blocks have 2-bolt mains on all 5 locations.
  • Uses + .300" tall stock 87-95 roller lifters.
  • Provisions for OE stock roller lifters & cams.
  • Uses 1981-1985 stock style oil pan & passenger side dipstick.
  • Uses stock stamped steel or plastic timing cover.
  • All OE bolt holes for starter, clutch ball, etc.
  • Oil restrictors available throught aftermarket resources.

CARB Warning

Follow EPA, CARB, and state regulations for engine changes

Emissions warning: this part is for vehicle engine changes, not direct oem engine replacements. In California, engine changes are legal when done in compliance with California bureau of automotive repairs (bar) engine change policy. For assistance, call bar referee at: (800) 622-7733. And see https://bar.Ca.Gov/consumer/smog_check_program/engine_changes. All customers must comply with federal epa mobile source enforcement memorandum no. 1a (and addendum) and all applicable state regulations when conducting engine changes. Improper installation and/or use of this part in California may subject the installer and/or owner to a $37,500 penalty per violation per vehicle, revocation of registration, loss of use on California public right of ways, and proof of correction for tampering. There are similar restrictions and penalties under federal law and laws of all states for use of this engine change part on makes or models of vehicles that render them noncompliant with applicable state and/or federal emission laws with penalties under federal law of up to approximately $45,268 per tampered vehicle and/or engine


MFG. Part #31161411
Bore Size3.750"
Cylinder WallSiamese
Sold in QuantityEach