There’s nothing quite like the tug on your back as you dip
into the torque generated by a big-block V-8. And with the
502 HO, you can experience the axle-twisting torque
created by GMPP’s legendary 502-cubic-inch Rat engine
at a more economical price.
The 502 HO is filled with a 4.00-inch forged crankshaft,
4.47-inch forged aluminum pistons, forged rods and a
high-lift steel roller camshaft—all ingredients for durable,
count-on-it performance—and it’s all topped with a set of
rectangular-port iron cylinder heads. The 8.75:1 compression
ratio is pump-gas friendly and makes the 502 HO a
great candidate to be upgraded to a supercharged street
engine, too!
GMPP finishes up the assembly with an aluminum dualplane
intake manifold, cast iron water pump, 6-quart oil
pan (with windage try), damper and 14-inch flexplate. You
finish it off with a carburetor, starter and ignition system—
all available from GMPP.
With 450 horses and 550 lb.-ft. of torque, the only thing
the 502 HO sacrifices is cost!

• TECH SPECS: 502 HO
• Part Number: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12568778
• Engine type: . . . . . . . . . . . . . . . . . . . . . . . . . Chevy big-block V-8
• Displacement (cu in): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
• Bore x stroke (in) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.47 x 4.00
• Block: . . . . . . . . . . . . . . . . . . . . cast iron with 4-bolt main caps
• Crankshaft: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . forged steel
• Connecting rods: . . . . . . . . . . . . . . . . forged steel, shot peened
• Pistons: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . forged aluminum
• Camshaft type: . . . . . . . . . . . . . . . . . . . . . . . . . . hydraulic roller
• Camshaft lift (in) . . . . . . . . . . . . . . . . . .510 intake / .540 exhaust
• Camshaft duration (@.050 in) . . . . . 211° intake / 230° exhaust
• Cylinder heads: . . . . . . iron rectangular port; 118cc chambers
• Valve size (in): . . . . . . . . . . . . . . . . . . 2.19 intake / 1.88 exhaust
• Compression ratio: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.75:1
• Rocker arms: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . stamped steel
• Rocker arm ratio: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7:1
• Water pump: . . . . . . . . . . . . . . . . . . . . . . . . cast iron, long-style
• Flexplate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-inch
• Recommended fuel: . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 octane
• Ignition timing: . . . . . . . . . . . . . . . . . . . . . . 36° total @ 3600 rpm,
• with vacuum advance disconnected
• Maximum rpm: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5500

INSTALLATION NOTES
• Requires addition of carburetor, fuel pump, starter, distributor
and ignition system.
• Clutch linkage boss is cast into block, but must be drilled and
tapped. When using cast iron exhaust manifolds, lower head
bolts may need to be replaced with bolts with shorter heads,
for clearance.
• Requires electric fuel pump because the Gen VI block has no
mechanical fuel pump boss.
• Comes with a 14-inch automatic transmission flexplate; use flywheel
P/N 14096987 and 11-inch clutch assembly for manual
transmission.
• Not intended for marine applications.