350 Bare Block


  • 350 bare block
  • 1986 and later style
  • 1-Piece Rear Main Seal
  • 4.000″ bore
  • Machined for hydraulic roller or flat tappets

Available on backorder

Due to world events we are working with our manufacturers every day to ship and receive parts. If the part you are looking for is time sensitive please give our team a call at 855-806-1147 before ordering to ensure it's availability.

Shipping is free, but there is a delivery fee for residential addresses.

350 Bare Block (1986–Later Style)

P/N 12691718

  • One-piece real main seal
  • Cast-iron 4-bolt block
  • 4.000″ bore
  • Machined for hydraulic roller or flat tappets



350 Bare Block

1986-Later Style

12691718 Chevrolet Cylinder Block

When building a mild Small-Block performance engine or a replacement for a stock engine, brand-new, production-based blocks from Chevrolet Performance give you strength, accuracy and peace of mind that can’t be assured in a rebuilt core. In addition, unlike so many of the used cores, this GM block features 4-bolt main caps for extra strength ヨ there’s no reason to settle for a 2-bolt block. Each new cylinder block is machined to production-spec tolerances and is manufactured to the exact specifications for 1986 and later engines with one-piece rear main seal.

Production-Based Block Technical Notes:

  • Standard 350 main journal sizes
  • Non-siamese bores
  • Production-spec cylinder wall thickness
  • Lifter valleys machined for hydraulic roller and flat tappet valve trains
Prop65WARNING: These auto parts can expose you to chemicals including phthalates and lead. Installing or using these parts can expose you to other parts containing these chemicals and to engine exhaust, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to