12498772 - GM Performance Parts ZZ383 Engine

Big Block Performance,
Small Block Price Tag

It all starts with a 383 cubic inch block and the legendary Fast Burn cylinder heads, offering an incredible 460 ft/lbs of torque @ 4500 RPM with a smooth linear delivery. The combination of a 4.000" bore and 3.750" stroke steel crank and a stout .509"/.528" lift hydraulic roller camshaft produces 425 HP @ 5400 RPM. GM testing utilized a single plane intake manifold (#809-12496822), Demon 750 cfm mechanical secondary carb, and 1-3/4" primary x 33" long headers with 4" collectors. A dual plane manifold (#809-12366573) can be used but will affect overall peak performance by 15-20 horsepower.

Specifications

Horsepower: 425 @ 5400 RPM

Torque: 449 ft/lbs @ 4500 RPM

Compression Ratio: 9.7:1

Block: Cast Iron 4-Bolt Main with 1-piece rear main seal

Crankshaft: Forged 4340 Steel (externally balanced)

Connecting Rods: Powdered Metal (special 383 version)

Pistons: Hypereutectic Flat Top with offset pins

Camshaft: Hydraulic roller, 222°/230° @ .050", .509"/.528" lift, 112° center lobe

Rockers: 1.5:1 Aluminum full roller self-aligning

Cylinder Heads: Aluminum Fast Burn 62cc chamber, 210cc intake runners, 2.00" hollow stem intake/1.55" sodium-filled exhaust valves, LT4 Corvette valve springs and lightweight retainers,
D-shaped exhaust ports, dual intake bolt pattern, and standard & centerbolt valve cover patterns

Additional Parts Included

8" balancer

12-3/4" automatic flexplate

4-quart oil pan with windage tray (5-quart capacity with PF35 filter)

Painted valve covers with oil cap (provisions for PCV breather)

Composite plastic front timing cover

Engine oil dipstick and tube (passenger side)

Brass freeze plugs

Fuel pump block-off plate

Engine lift tabs

Recommended Components

Long, cast iron water pump (standard V-belt rotation with 1979-86 power steering pump boss)

Vortec Single Plane Manifold #809-12496822 (to achieve 425 HP)

Vortec Dual Plane Manifold #809-12366573 (when hood clearance is a problem; peak power may decrease 15-20 HP)

Warranty Information

These kits, put together by JEGS Professionals, include:

GM Performance Parts ZZ383 Engine

GM Performance Parts Intake Manifold"

JEGS Intake Gaskets

JEGS Intake Manifold Bolts

Demon Speed Demon Carburetor

JEGS Dual Feed AN Fuel Line Kit

JEGS Fuel Pressure Gauge

JEGS Carburetor Stud Kit

JEGS RTV Silicone Gasket Maker

View in Current Catalog

Complete list of GM Performance Parts ZZ383 Engine

12498772 - GM Performance Parts ZZ383 Engine Details

Note: This engine has provisions for a mechanical fuel pump, however the fuel pump pushrod and adapter plate are not included.

The engine block and cylinder heads are drilled and tapped for all standard accessory mounting bracket locations including two clutch ''Z-bar'' ball stud locations - standard and 1963-82 Corvette.

Front face of engine block is also drilled and tapped for the 1955-57 Chevy type motor mounts. If using these motor mounts, the mounts will need to be modified to clear the 8'' harmonic balancer on this engine.

If a short water pump is to be used on this engine, there will be clearance problems between the water pump backing plate bolt heads and the composite timing cover used on the Fast Burn 385. Many times this problem can be fixed easily by replacing the bolts on the water pump backing plate with button head Allen bolts. If this approach does not work, the timing cover will need to be replaced with a sheetmetal or any chrome unit. Any small block Chevy timing cover will work on the Fast Burn 385. If the timing cover is replaced, dowel pins are also needed.

This engine comes equipped with a 12-3/4'' automatic transmission flexplate which works with most TH-350 and 700R4 torque converters. If a TH-400 is being used, a 14'' flexplate must be used.

If this engine is to be used behind a manual transmission, two manual transmission flywheels are available, a 12-3/4'' or a 14''. The 12-3/4'' flywheel is used with 10'' to 10-1/2'' clutches and the 14'' flywheel is used with 11'' to 12'' clutches. Flywheel bolts and a pilot bearing are also required.

It is possible to retrofit this engine with a L98/LB9 TPI system. Special intake manifold 12498060SD along with 24 lb. injectors PTE24 must be used (Available through GM Performance Parts). Custom computer re-programming is also necessary.

There is a confusing history of spark plugs that have been used in the Fast Burn 385 throughout it's lifetime. Originally, most of these engines used a (not commonly available) AC Delco MR43LTS spark plug, which is a marine version of the R43LTS (it has nickle plated barrels to resist corrosion). These plugs can be replaced by an AC Delco R42LTS (commonly available). If some extra clearance is required, a gasket seat plug can also be used (cylinder heads accept either style). The gasket seat equivalent is FR3LS (also commonly available). All plugs should be gapped at .045''.