ATK Engines SP97-B Chrysler Hemi, 392 Stroker Short Block, Boost

The ATK SP97-B is a short block built on the Gen III Hemi 392 stroker combination: a 3.927 in. bore and 4.050 in. stroke on a 2003-2008 Hemi block fitted with ARP main studs. A Scat 4340 forged, internally balanced crank turns Scat 4340 forged H-beam rods at 6.125 in. with ARP 2000 bolts, under forged flat-top pistons dished 2cc.

Who this short block suits

This one is built with boost or nitrous in mind rather than a naturally aspirated street combination: the ring pack uses a plasma-moly set with a steel top ring gapped specifically for forced induction or nitrous use. Compression runs from roughly 9.1:1 to 9.8:1 depending on the combustion chamber volume of the heads you choose.

What to check before you buy

• Here, too, factory hands set the cam bearings to spec, and the oil galley plugs come sealed from the factory, with a head gasket clearance of .028 in. or to your application.
• Heads, camshaft, intake, and ignition are not part of a short block; plan those separately for your Hemi build.
• Internal engine balance is used here, so match your balancer and flexplate or flywheel accordingly.

Common questions

Is this a complete engine? No, it is a short block: block, crank, rods, and pistons only.

What break-in oil does ATK specify? A non-synthetic 5W20 for roughly the first 3,000 miles.

Is this a street cam? No, the ring package here is specifically set up for boosted or nitrous use.