ATK Engines SP52NB Chevy 377 Stroker Short Block, 3.7cc Flat

Reusing a good set of cylinder heads is the point of the ATK SP52NB short block. It supplies a new American-made, 1-piece-seal Chevy block, with Scat handling the spin parts: a nodular-iron crankshaft and forged connecting rods, both riding on ARP 8740 bolts, finished with forged flat-top pistons dished only 3.7cc, so the bottom end is ready and your current heads bolt straight on.

Who this short block suits

Those near-flat pistons push static compression noticeably higher than a dished piston at the same chamber size, running roughly 10.5:1 up to 12.1:1 depending on the head you install, varying with deck height and gasket thickness. That puts this ahead of ATK's dished-piston 377 short block for a buyer chasing more compression with heads already on hand.

What comes with it

• Factory hands set and seal the freeze plugs and oil galley plugs here, while the cam bearings are already clocked to spec.
• Heads, camshaft, intake, oil pan, and timing cover are not part of a short block and must be sourced separately.
• The externally balanced 168-tooth flexplate or flywheel pattern matches the Scat rotating kit used here.

Common questions

Can I bolt my current heads onto this? That is the intent of this short block; check your head's chamber volume against the compression figures above.

What oil does the break-in call for? ATK specifies non-synthetic 10W30 for roughly the first 3,000 miles of use.

Is the block the same as ATK's other 377 short block? It uses the same American-made casting, but with flat-top pistons instead of a dish. California requires BAR compliance for engine swap installations.