1978 Pontiac Firebird Trans Am 400 CID
Automatic Transmission Engine Specifications

Engine Code

YA (early production)

Engine Code

YU (late production)

Engine RPO

L78

Displacement

400 CID

Bore x Stroke

4.1212" x 3.750"

Compression Ratio

7.6:1

Horsepower @ RPM

180@3600

Torque (Lb/Ft) @ RPM

325@1600

Head Casting

NA

Carburetor

4-bbl

Carburetor - Federal

17058276 (early production)

Carburetor - Federal

17058278 (late production)

Camshaft

Part #

527471

Lift, I/E

/

Rocker Arm Ratio

1.5:1

Duration I/E - Degrees

NA / NA

Overlap - Degrees

NA

Intake Valve Dia -

2.11"

Exhaust Valve - Dia

1.66"

Distributor

1103359