The all-new ZL427 Gen IV LS7-based aluminum short block builds on the phenomenal success of our original ZL402 short-blocks. This new package uses the same race proven internals as our short-block predecessor but features the all-new LS7 block. Designed primarily for use in any late-model GM LS Car/Truck/SUV, it makes a great choice for most street rods/muscle-cars.

You won't find a higher quality, better value LS7 stroker short block anywhere!

This package (12427M58) is in short-block form, minus manifolds, camshaft, oil pump, and other components. The advantage of this approach is it allows you to pick a combination best for you. SLP also sells the 427 packages in long block form.

NOTE: While placing your order, please specify make and model year that the 427 will be installed in. Be sure to order the correct ZL427 engine with the proper style reluctor wheel for your application (reference chart below). SLP's harmonic balancer/under-drive pulley is required for proper installation (or an equivalent pulley that is properly keyed) a stock balancer/pulley will NOT fit.

ZL427 LS7 Aluminum Short Block Includes the following:
Built entirely from brand new parts
Sold outright, no cores required.
GM LS7 aluminum block
427-CID displacement
4.000 Callies 4340 forged steel crankshaft, balanced to rotating assembly
4.125" SLP/Manley 2618 forged alloy pistons with -9.00cc dish (includes new rings and full-float pins)
6.125" SLP/Manley 4340 forged steel H-beam rods
Includes new, factory-installed cam bearings; Clevite rod and main bearings
11:1 compression ratio (nominal; ultimate compression ratio will depend upon heads and gaskets used)
58 Tooth reluctor wheel
Designed for naturally aspirated applications
Capable of supporting up to 700+ HP
Meticulously assembled by SLP to OEM tolerances and specifications
Includes Front Cover
Includes Valley Cover
Includes Spacers for oil windage tray
Oil pump, camshaft, pans, plates, and covers not included
ZL427 OEM-quality fender badges (QTY-3)