CMW Trucks - 1947 - 1972 Chevy Truck Parts


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HT502 - Emission Legal Truck Conversion Kit

The GM Performance Parts HT502 Emission Legal (50 state) Conversion Kit is designed for 1991-93 Chevrolet and GMC 10-, 20-, and 30-series trucks with two-wheel drive, originally equipped with a 454 TBI engine and 4L80E automatic overdrive transmission. This kit will dramatically improve the towing capabilities of your truck, as the HT502 is a direct bolt-in replacement for any high-mileage 454. With more cubic inches, improved efficiency, and more horsepower and torque, the HT502 will give your aged GM truck substantially more torque than the factory 454 ever delivered.

The The GM Performance Parts HT502 Chevy crate engine comes assembled with an oil pan, timing set, valvetrain, valve covers, and damper. You simply swap the outgoing engine’s TBI manifold and throttlebody, ignition system, and other components onto this engine. A new PROM electronic control module (ECM) chip is included, along with a detailed instruction guide. Additionally, the kit includes transmission, exhaust, and fuel system upgrades to make the swap easy and complete.

Technical Note: This kit will not work on four-wheel drive trucks, due to an exhaust interference.

Possible Applications

  • Your big-block mud-bogger
  • A tow rig that needs an attitude adjustment
  • A pick-up truck that can pound most sports cars

*Applications have not been validated. They are merely suggestions of how you might enjoy your GM Performance Parts crate engine. Some applications may affect engine warranty. See specific warranty information. Some applications may not be emission legal; check state and local ordinances.

Engine Part Number 88890533
Displacement (cu in): 502
Bore x stroke (in): 4.47 x 4.00
Block (P/N 10237292): Cast iron with 4-bolt main caps
Crankshaft (P/N 10183723): Forged steel
Connecting rods (P/N 10198922): Forged steel, shot peened
Pistons (P/N 12533507): Forged aluminum
Camshaft type (P/N 12552296): Hydraulic roller
Camshaft lift (in): .480 intake / .483 exhaust
Camshaft duration (@.050 in): 204'c1 intake / 209'c1 exhaust
Cylinder heads (P/N 12552888): Iron round port; 118 cc chambers
Valve size (in): 2.07 intake / 1.73 exhaust
Compression ratio: 8.75:1
Rocker arms (P/N 12523976): Stamped steel
Rocker arm ratio: 1.7:1
Flexplate (P/N 10185034): 14"
Recommended fuel: 92 octane
Ignition timing: 4'c1 BTDC
Maximum rpm: 5500

Chevy Performance HT 502 engine image

Part #:88890533

HT 502 dyno image

  • NOTE: Distributor with melonized steel gear MUST be used with long blocks and partial engines with steel camshafts, or engine damage will occur. GMPP distributor P/N 93440806 is recommended.
  • Technical Note: This kit will not work on four-wheel drive trucks, due to an exhaust interference.