Engines and Components› Pistons and Piston Rings

KB

Hypereutectic Piston Set, 4.030" Bore, Flat Top with 7cc

$515.55

SKU: KBPKB120.030

In Stock
In Stock
Ships by Sep 12
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Advanced — 4+ hours

Overview

The Keith Black KB120-030 is a set of eight hypereutectic pistons designed for Small Block Chevy 350 engines. These pistons feature a flat top with 7cc valve reliefs and a 4.030-inch bore.

Constructed from a 390 aluminum alloy with 16% silicon, they offer low expansion for tighter piston-to-wall running clearance. The set includes CNC-machined pin bores, accumulator grooves, machined oil returns, and diamond-finished skirts.
Show original supplier description
The Keith Black KB120-030 piston set is engineered for high-performance builds, including marine, drag race, circle track, street, and towing applications. These hypereutectic pistons are forged from a 390 aluminum alloy with 16% silicon, providing low expansion characteristics for a tighter, more efficient piston-to-wall running clearance. The set includes eight flat-top pistons with a 7cc valve relief, a 4.030-inch bore, and a compression height of 1.561 inches. Key features include fully machined head and valve reliefs, triple spiral lock rings, and CNC-machined pin bores for precise alignment and sizing. They also incorporate an accumulator groove to aid compression ring seal, machined oil returns, and diamond-finished skirts to reduce scuffing and overheating. Wrist pins and spiral lock rings are included with the set. These pistons are designed for SB Chevy 350 engines with a 3.480-inch crankshaft stroke and a 5.700-inch rod length. The advertised piston weight is 587 grams, with a 145-gram wrist pin. Compression ratios vary depending on combustion chamber volume: 10.9:1 for 58cc, 10.4:1 for 62cc, 10.2:1 for 64cc, and 9.0:1 for 76cc chambers. Note that piston rings (5/64 x 5/64 x 3/16) are not included.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

Fitment Guaranteed

Don’t gamble
on fit.

Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

Available on iOS & Android

Specifications

BrandKB
Part NumberKBPKB120.030
CategoryEngines and Components

We’re here — turning wrenches, just like you.

Call us, follow along, or come say hi.

(760) 282-4645 Instagram Google

Buy with Confidence

Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

View Full Return Policy

Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

View Full Shipping Policy