Enginetech PK3B

Enginetech PK3B is a complete brass engine expansion-plug kit, commonly called a freeze-plug or core-plug kit, for classic Chevrolet Big Block engines. It restores the casting openings in the cooling jackets and other machined block passages during an engine rebuild.

Application / fitment

PK3B is primarily designed for Chevrolet Mark IV Big Block engines using 1 3/4 in block core plugs. Typical applications include:

• Chevrolet Big Block 396 / 6.5 L
• Chevrolet Big Block 402 / 6.6 L
• Chevrolet Big Block 427 / 7.0 L
• Chevrolet Big Block 454 / 7.4 L
• selected Chevrolet, GMC and Pontiac vehicles using these engines, generally from the mid-1960s through 1990
• selected pickups, vans, medium-duty trucks, specialty vehicles and marine installations using a compatible Mark IV Chevrolet Big Block

Fitment condition: compare every plug diameter and location with the actual block before installation. Do not automatically apply this kit to later Gen V/Gen VI Big Blocks or aftermarket blocks because plug layout and sizes may differ. Final fitment is determined by block casting, not vehicle model alone.

Installation note: remove the old plugs without damaging their bores and thoroughly flush rust and scale from the cooling jackets. Clean and degrease every bore. Drive each plug squarely with a suitable installer and use a sealant intended for engine core plugs. Pressure-test the cooling system after assembly.

Technical information

• manufacturer: Enginetech
• part number / SKU: PK3B
• type: engine expansion plug / freeze plug kit
• primary application: Chevrolet Mark IV Big Block 396–454
• main plug material: brass
• threaded pipe-plug material: steel
• main block plug diameter: 1 3/4 in / 44.45 mm
• typical contents: eight 1 3/4 in brass plugs, one 5/8 in small plug and seven 1/4 in pipe plugs
• typical component count: 16
• coverage: one engine
• sale unit: 1 kit