The first-generation Chevrolet small-block V-8 block remains an iconic and brilliant
design some 55 years after being introduced in 1955. 

The Gen I small-block Chevy quickly became the engine of choice for many hot rodders
and the preferred engine block for racers seeking to build a lightweight, simple, affordable
and versatile engine. The original cast iron Chevy block was used in almost every type of
engine from injected nitromethane-burning units to alcohol-burning small
blocks that powered Indy 500 champ cars.  But despite its many virtues, the
ubiquitous Chevy-designed small block isn't perfect.

Engine technology has changed dramatically since the early '50s, and what
seemed like good ideas five decades ago simply no longer do the job in the
21st Century.  While the timeless small-block design still provides the basic
architecture for the aftermarket blocks, the
performance industry has improved on and
refined virtually every component of the
original engine, from carburetor to the oil pan,
and that includes a re-design of the cylinder

A great example of Dart’s improved design of Chevy’s small block is Special High Performance (SHP) cast-iron small block. The Dart SHP block incorporates the best features of OEM blocks with some technological performance updates -- updates that aren't available in any GM production casting. The improved DART block was designed to support up to 600 horsepower. The Dart SHP block solves the persistent problems of the classic Chevy small-block V-8.

Problem: Scarce Cores

Although GM has produced more than 90 million small-block V-8s, very few of the survivors are suitable for high-performance applications. The supply of heavy-duty blocks from the 1960s and '70s has been thoroughly picked through, leaving mostly blocks with damage such as spun bearings, cracked main webs, and split cylinder walls in salvage yards. The highly sought after by engine builders of “big” small block Chevys, the  400-cubic-inch -blocks with 4.125-inch diameter cylinder bores – the key component for any big-inch small-block – are virtually extinct.

Late-model production blocks also have serious drawbacks. Cylinder walls are perilously thin in many of these lightweight castings. Mechanical fuel pump mounts were eliminated when EFI arrived, and the one-piece rear crankshaft seal introduced in 1986 is incompatible with most high-performance crankshafts and flywheels.


If you'd rather spend more time building and racing and less time picking through grime-encrusted blocks at a muddy, back-road salvage yard, then a redesigned SHP cast iron block from a aftermarket manufacturer like Dart or other well known U.S. manufacturers is what you need.

DART’s SHP block eliminates the time, expense, and hassle of scouring junkyards and chasing down classified ads to find a usable core. By the time an enthusiast buys a used block and has it cleaned, pressure checked, decked, bored, and honed with a torque plate, the cost is more than what they would spend to buy a new SHP block that's already CNC machined to precise tolerances.

A Dart SHP block is virtually ready to assemble out of the box; it just requires honing the cylinder bores for piston clearance. Best of all, SHP blocks with 4 1/8" cylinder bores are readily available. Dart offers the SHP block with a choice of two cylinder diameters: 4.00-inch (part No. 31161111) and 4.125-inch (part No. 31161211). This isn't some cheap offshore knock-off; the SHP block is cast in American foundries and machined at Dart's manufacturing facility in Michigan to ensure quality.