You will notice that in some cases, a specific piece of data is blank. We simply left the space blank because it was data that we did not have. As more information becomes available to us, we will update these specifications.
| 1967 - 1969 L88 Engine Specifications |
| |
1967 |
1968 |
1969 |
| General |
| SAE Gross Horsepower (advertised): |
430 hp @ 5,200 rpm |
| SAE Net Torque (advertised): |
460 ft. lbs @ 4,000 rpm |
| SAE Gross Horsepower (actual): |
Approx. 550 - 570 hp @ 6,200 - 6,400 rpm |
| SAE Net Torque (actual): |
Approx. 470 ft. lbs @ 5,200 rpm |
| Displacement: |
427 CID, 6997 cc |
| Bore and Stroke: |
4.251 in. x 3.760 in. (108.0 x 95.2 mm) |
Compression Ratio:
Maximum:
Nominal: |
12.8:1
12.5:1 |
12.9:1
12.0:1 |
| Camshafts |
| P/N: |
|
3928911 |
3928911 |
| Casting No: |
|
3928911 |
3928911 |
| Base Circle |
32.8 mm (1.291 in.) |
NA |
NA |
| Lobe Lift |
9.9 mm (0.39 in.) |
NA |
NA |
| Supplier |
GM Bay City |
NA |
NA |
| Connecting Rods |
| Length: |
6.135" |
NA |
NA |
| Crankcase |
| Descriptions |
Open deck 4-bolt fastening per bearing panel |
| Cylinder Head Volume: |
|
103.3 |
114.8 |
| Deck Clearance: |
.008 |
| Deck Height |
9.800 in. |
| Head Gasket Thickness (Compressed): |
.043 |
| Head Gasket Volume: |
10.81 cc |
| Min. Combustion Chamber Vol: |
|
74.15 cc |
73.47 cc |
| Crankshaft |
| Material: |
Forged premium alloy 5140 steel with "tuftride" surface coating |
| Cylinder Head |
| Casting Number: |
|
3919842 |
3946074 |
| Manufacturer: |
Winters Foundry |
NA |
NA |
| Material: |
Aluminum - (Early prototypes used cast iron) |
| Induction |
| Make / Type: |
850 CFM Holley 1 x 4 bbl. D.D. |
| Material: |
Aluminum |
| Model No. - Auto. Trans: |
NA |
NA |
3955205 |
| Model No. - Man. Trans: |
|
3925519 |
3955205 |
| Intake Manifold Cast. No: |
|
3885069 or 3933198 |
3933198 |
| Lifter Type: |
Mechanical - Solid |
| Rocker Arm Ratio: |
|
1.70:1 |
1.70:1 |
| Pistons |
| Description: |
dome head valve cutout |
| Displacement of Dish/Dome, etc: |
|
45.7 cc |
51.7 cc |
Height of Dome or
Depth of Dish: |
|
.454 |
.454 |
| Manufacturer: |
TRW |
NA |
NA |
| Material: |
High-silicon-alloy aluminum |
NA |
NA |
| Timing |
| Check Cl: |
|
Intake: .020
Exhaust: .020 |
Intake: .020
Exhaust: .020 |
| Opens: |
|
Intake: 61o BTC
Exhaust: 108o BBC |
Intake: 61o BTC
Exhaust: 108o BBC |
| Closes: |
|
Intake: 113o ABC
Exhaust: 72o ATC |
Intake: 113o ABC
Exhaust: 72o ATC |
| Overlap: |
|
Intake: 133o
Exhaust: |
Intake: 133o
Exhaust: |
| Duration: |
Intake: 332o
Exhaust: 333o |
Intake: 354o
Exhaust: 360o |
Intake: 354o
Exhaust: 360o |
| Lift: |
Intake: .560 @ .024 - lash
Exhaust: .580 @ .026 - lash |
Intake: .540 @ .022 - lash
Exhaust: .560 @ .024 - lash |
Intake: .540 @ .022 - lash
Exhaust: .560 @ .024 - lash |
| Springs |
| Outer Closed: |
|
Intake: 77 @ 1.88 Exhaust: 77 @ 1.88 |
| Outer Open: |
|
Intake: 190 @ 1.344 Exhaust: 195 @ 1.324 |
| Inner Closed: |
|
Intake: 43 @ 1.78 Exhaust: 43 @ 1.78 |
| Inner Open: |
|
Intake: 100 @ 1.244 Exhaust: 103 @ 1.244 |
| Valves |
| Head Diameter: |
Intake: 2.19 Exhaust: 1.88 |
| Angle of Seat & Face: |
Intake: 45o Exhaust: 45o |
