Speedmaster®
Oldsmobile 400 425 455 188cc 77cc Hydraulic Flat Assembled Cylinder Heads
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Product Information
Specs
| Brand: | Speedmaster |
| Part Number: | PCE281.2152 |
| Part Type: | Cylinder Head [Assembled] |
| Product Line: | Hydraulic Flat Tappet |
| Cylinder Head Style: | Assembled |
| Cylinder Head Material: | Aluminum |
| Cylinder Head Finish: | Natural |
| Combustion Chamber Volume (cc): | 77 cc |
| CNC-Machined Combustion Chamber: | No |
| Intake Runner Volume (cc): | 188 cc |
| Exhaust Runner Volume (cc): | n/a |
| CNC-Machined Intake Runner: | No |
| CNC-Machined Exhaust Runner: | No |
| Intake Port Shape: | Rectangular |
| Intake Port Location: | Standard |
| Exhaust Port Shape: | Square |
| Exhaust Port Location: | Standard |
| Spark Plug Style: | OEM |
| Comp. Valve Job: | No |
| Intake Valves Included: | Yes |
| Intake Valve Diameter (in): | 2.072 in. |
| Exhaust Valves Included: | Yes |
| Exhaust Valve Diameter (in): | 1.680 in. |
| Valve Springs Included: | Yes |
| Maximum Valve Lift (in): | 0.615 in. |
| Outside Diameter of Outer Spring (in): | 1.450 in. |
| Damper Spring Included: | Yes |
| Number of Springs Per Valve: | Dual |
| Retainers Included: | Yes |
| Retainer Material: | Chromoly steel |
| Locks Included: | Yes |
| Lock Style: | 10 degree |
| Valve Stem Seals Included: | Yes |
| Valve Stem Seal Style: | Positive stop |
| Rocker Arm Studs Included: | No |
| Rocker Arms Included: | No |
| Rocker Arm Nuts Included: | No |
| Guideplates Included: | No |
| Valve Cover Mounting Style: | Center & Perimeter Bolt |
| Accessory Bolt Holes Drilled: | Yes |
| Intake Valve Angle: | 18 deg. |
| Exhaust Valve Angle: | 18 deg. |
| Valve Guides Included: | Yes |
| Valve Guide Material: | Bronze |
| Valve Seats Machined: | Yes |
| Valve Seat Machine Style: | 3-angle |
| Valve Seat Material: | Ductile iron |
| Steam Holes Drilled: | No |
| Oiling Style: | Through pushrod |
| Machined for O-Ring: | No |
| Heat Crossover: | No |
| Quantity: | Sold as a pair. |
Description
Assembly Specifications
Max Lift: .615
Coil Bind: .1.125
Intake Install: 140lbs @ 1.8
Exhaust Install: 140lbs @ 1.8
Closed Seat Pressure: 145lbs
Open Seat Pressure: 345lbs
Warranty Information
12-Month Limited Worldwide Warranty
Prop 65 Warning
This product may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.
Installation Guide
Our AI assistant generates a step-by-step guide for this product — covering installation, maintenance, and troubleshooting.
This AI-generated guide is for general reference only and does not constitute official Speedmaster product documentation. Always verify fitment, torque specifications, and safety requirements before installation.