Compression Pressure

1966 Chevrolet Chevy II Base, Not Available, 2.5L Eng, Automatic Trans, Trans Mfr CD THM400SECTION Compression Pressure

At cranking speed with throttle wide open and all plugs removed. Maximum variation between cylinders 15 lbs.

283" 150 lbs.
327", 250, 275, 300 HP 160 lbs.
  350 HP 150 lbs.
396" 160 lbs.
427" 390 HP 160 lbs.
  425 HP 150 lbs.
VALVE TAPPET CLEARANCE

All Except 427" 425 HP Zero Lash, Hydraulic
427" 425 HP .020" Int..024" Exh. (Hot)
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.