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427ci Dart LS Next Iron Short Block for Boost, 1/2" Head Studs Included

Type: Engine Packages
Vendor: Borowski Race Engines

Description:

This 427ci LS iron short block is ideal for intermediate range boost. The Dart block is a big leap over a GM block as is the Callies 8-counterweight crank (details below). Add in the Callies rods, Diamond pistons, upgraded fasteners, our precision CNC machining and you've got a dependable short block that will last. Here is what you're getting:
  • Dart LS Next SHP Block - 4.125" bore
  • Callies' fully counterweighted (CCW) Apex crankshaft
  • Calico coated rod and main bearings  
  • Callies Ultra I-Beam Enforcer connecting rods
  • Diamond R-Series 2,000 hp-rated pistons
    • .225 wall wrist pin
    • Available with either 15-degree (LS3) or 12-degree (LS7) valve reliefs

John McGhee from Cutaway Racing was with us at PRI 2023.  See him explain why he likes this build so much and the derivative long block topped with our All Pro CNC ported heads:

The engine block is the foundation any build. The Dart LS Next design is both solid and user friendly. No one has been using them longer than us. Dart's late founder, Richard Maskin, personally presented us with Serial #0002. (Dart cut up #0001 for QC checks). 

  • Full side skirts to accommodate OE oil pans
  • Accepts LS style Oil filters
  • Retains all factory bolt hole locations
  • Longer cylinder sleeves to keep piston fully supported 
  • Priority main oiling
  • 4 bolt splayed main saddle for greater structural strength

Fasteners are literally what hold the engine together.  We replace the main bolts with main studs for more precise and reliable clamping force. The Dart block's 6-bolt per cylinder design provides a big jump in applied clamping force over a 4-bolt design. We take this short block a big step further by machining the block to accept the included 1/2" head studs.  These exert 40% higher clamping force than comparable 7/16" studs as explained in this blog. The Dart 1/2" head stud kit is included in the indicated price. Getting the fastener kit with the short block is convenient. More importantly, getting them from us assures authenticity. 

The center counterweighted Callies Apex crank has a 4.000" stroke and is made from extremely clean 4340 Timken alloy. The center counterweights are a major upgrade as they increase the cranks stiffness by about 25% while reducing harmonics. The net result is less stress on the main bearings and longer engine life. Watch the video below to learn more.

All Callies Ultra rods are made from Timken 4330 steel alloy. The Enforcer design leaves a little more material in key locations for greater strength. I-Beam Enforcer rods are standard (see video below). Callies Ultra H-Beam rods are also available.


This combination of Apex crank and Ultra rods can be modified depending on end use application. Callies' more budget-friendly Compstar line is great for lighter boost.  Their 100% Made in USA Magnums are their best forged crank. Popular options at the Magnum level include larger diameter lifter bores, CA-625 rods bolts and aluminum instead of steel connecting rods. Call us at 815-725-2727 for help in sorting through the various options.

Topping off the rotating assembly are Diamond's Race Series pistons which are machined with their newest and most precise CNCs in Clinton Michigan. Among their features :
- 3D milling on piston crowns for ready to install finish
- Valve pockets designed to work with most aftermarket cylinder heads
- Offset pins for quiet operation
- Moly skirt coating for friction loss and skirt wear protection
- Side gas ports for better ring seal
- 2618 material for High HP-NOS-Boost applications
- You can select either the LS3 or LS7 piston design.  Dish-type is standard but there are a wide range of options.

Calico-coated Clevite bearings are standard. The windage tray we make for these blocks is an available add-on.

The machining of your short block is as important as the parts selection. BOROWSKI RACE ENGINES, INC. boasts state-of-the-art CNC machining equipment which empowers our staff to build the best engines available. Primary machining is done on our Rottler 4-axis CNC mill and CNC diamond hone. Together, these provide the most precise achievable dimensions and surface finish yielding in turn, the best performance and longevity.

Last but not least, the skill of the people who finish-machine and assemble your short block is just as important as the parts, machining and design. We've got some of the best around and we have spent a lot of time and money on their training. This investment in our people was recognized by the State of Illinois with their Business Leadership award. We have also been recognized by Engine Builder Magazine as Race Engine Builder of the Year.

Call 815-725-2727 to discuss your engine requirements or just click on your selection to place an order.

Notes:
  1. This short block is not intended for pollution-controlled applications and may not be legal for transportation use.
  2. The crankshaft photos and video show the available Callies Magnum crank whose appearance is nearly identical to that of the standard Apex crank.

Built by people who love motorsports for people who love motorsports

Payments accepted: ACH, wire transfer, cash, money order, certified check, cc with surcharge

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