ATK Engines SP53 Chevy 383 Stroker Short Block

ATK's SP53 is a short block built around the familiar GM small-block bore pattern taken out to 383 cubic inches, paired with a 3.750 in. stroke. The rotating assembly is forged, running ARP 8740 rod bolts and moly rings, and arrives machined, clearanced, balanced, and blueprinted, leaving the compression, cam, and top end for you to pick.

Who this short block suits

A short block hands the finished combination over to the builder rather than fixing it at a set power rating, which suits someone who wants to decide how mild or aggressive the completed engine runs. ATK describes the block as handpicked and seasoned, with aligned and honed main bores and a 4-bolt main pattern, and the main bearings and journals are already prepped for assembly.

What to check before you buy

• No cylinder heads, camshaft, intake manifold, oil pan, water pump, or harmonic balancer ship with this short block.
• The crankshaft is described as nodular iron with a 3.75-inch stroke, giving the 383 displacement when paired with the listed bore.
• Confirm exact rod and piston style with us before ordering.

Common questions

Is this assembled? Yes, the short block arrives assembled, machined, and balanced, ready for heads and a cam.

Does it include a flexplate or flywheel? No, neither ships with this short block.

What's the stroke length? 3.75 inches, which is what takes this block out to 383 cubic inches.