GM 383 Short Block Plus
HP & Torque: 432 HP / 450 FT LBS
Compression Ratio: 9.5:1
Forged Pistons
Forged Crank
Part #: BP38321SP


4 Bolt main
4.00" bore
Passenger side dipstick
Align honed main bearing bore

Cylinders honed on computer controlled machine to within .0002 straightness and roundness

Cylinders are sonic tested for thickness

Rotating Assembly:

New forged crankshaft, 3.75" stroke
Forged pistons, 18CC Dish
Forged rods with 150,000 PSI bolts
Hastings moly rings
Melling high volume oil pump
Hydraulic roller cam
Heavy duty double roller timing set
Harmonic balancer

Cam Specs:

Cam Type: Roller, Lift with 1.6 rockers .528 Intake .536 Exhaust,  221 Intake / 226 Exhaust duration @ .050 - 110 degree lobe separation

Ignition Timing:

34 degrees total (at 3500 RPM)

Also Includes:

Oil pan and timing cover
Brass freeze plugs


Bore and stroke combination makes this crate engine a 377ci displacement

This engine requires a non-weighted 8" harmonic balancer (included), and late 350ci weighted flexplate/flywheel.

The HP and Torque numbers derived from dyno testing with a 750cfm carb, and with H8002K cylinder heads installed.

*A bronze distributor gear is NOT recommended on this engine

Not for use in pollution controlled vehicles.

Share this Engine!

BP GM Product Line

GM Shortblocks

GM Performance Engines

GM Pro Series Engines