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