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88890534 - GM HT502 502CID 377HP Crate Engine

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The key to towing performance is torque, and the HT502 crate engine has got a whole lot of it.

Not only does this crate engine make torque, but it makes it right where you need it, way down low. With 512 Ft/Lbs. of torque at an incredibly low 2800RPM and 377 horse power at 4500 RPM, this engine will climb hills, accelerate onto the highway and pull out to pass with the sort of confidence that you've come to expect from a GM Performance Parts crate engine.

So for not too much more than a rebuild of your tired big block tow motor, you can step up to an all new HT 502 developed specifically for towing and heavy vehicle applications in 20 and 30 series light duty trucks. If you're concerned about durability, don't be. We've used the same four bolt block that we use in our other high performance 502's, and filled it with a forged crankshaft, forged connecting rods, and forged pistons. It even has a steel roller camshaft, designed to work in perfect harmony with the high velocity cast iron cylinder heads. The heads, with their moderately sized valves and round intake ports, ensure maximum cylinder fill at low RPM, and that means excellent low RPM efficiency that equates to maximized low end power and torque.

The 502 Truck Conversion engine comes assembled, but need your intake manifold, carburetor, water pump and distributor to run. It's time to upgrade, and GM Performance Parts has your engine, the HT 502 is a High Torque workhorse that will get you, your trailer and your crew to the races without even breaking a sweat. The HT 502 is intended for 1970 and earlier Chevrolet and GMC 20-series and 30 series trucks.

The HT 502 is not intended for marine use, and should only be used in 1973 and earlier pre-emissions street vehicles or any year off road vehicles. Technical Notes: Fully assembled, less intake manifold, distributor, water pump and exhaust manifolds. Includes engine assembly, instructions and decals.

Power: 377 HP @ 4500 RPM, 512 ft. lbs. of torque @ 3300 RPM
Displacement: 502 CID
Bore x Stroke: 4.47” x 4.000”
Compression Ratio: 8.75:1
Recommended Fuel: 92 Octane
Block: Cast Iron, 1 piece rear seal, 4-bolt main caps
Crankshaft: Forged Steel
Connecting Rods: Forged Steel
Pistons: Forged Aluminum
Camshaft: Steel Hydraulic Roller Tappet
Cam Lift: .480” Intake / .483” exhaust
Cam Duration @ .050”: 204 deg. Intake / 209 deg. Exhaust
Lobe Separation: N/A
Cylinder Heads: Cast Iron Oval Port
Combustion Chamber: 118cc
Valves: 2.070” Intake/ 1.73” Exhaust
Rocker Arms: Stamped Steel, 1.7:1 Ratio
Balance: External
Maximum GM Recommended RPM: 5500
Ignition Timing: Base 4 degrees BTDC, 26 degrees total

Engine Includes:
• Fully GM assembled long block
• Black Cast Aluminum Valve Covers
• Oil pump, pick-up and oil pan
• Spark Plugs
• 14” Auto Trans Flexplate
• 8” Harmonic Balancer
• Front timing cover
• Oil Filter and Adapter
• Passenger Side RH Oil Dipstick and Tube

General Motors limited 2 year / 50,000 mile parts & labor warranty. Click on Document tab above for full details.

Related Engines:
GM 502 450HP Crate Engine
GM 502 600+HP Fully Assembled Crate Engine
GM Big Block Serpentine Accessory Drive System

Application List


Shipping Information

  • Item Requires Shipping
  • 650.0 lbs.
  • W40.0000” x H32.0000” x L37.0000”
  • Free Shipping!
  • FREE 48 State Truck Freight Shipping (International shipping will require freight quote)

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