WANNA PISS OFF EVERYBODY? YEAH, THAT KIND OF FAST. (R-K)

SEE BELOW FOR LONG BLOCK SPECS

1500+hp Capable LONG BLOCK ASSEMBLY with no covers, gaskets, pan, or accessories.

THIS IS A MMRE/RACE-KING MODIFICATION FOR THE

GPI Boostmaster 396 – Built for Boost

AND INCLUDES CUSTOM FITMENT AND MODIFICATIONS TO THE ASSEMBLY BY MADDOX MOTORS RACING ENGINES

Forged for Forced Induction. Engineered for Excellence.

SAVE A COUPLE GRAND NOW, ACCEPTING PRE-ORDERS FOR CHRISTMAS!!

LIMITED TIME OFFER - REGULAR PRICE IS $21,889

GPI BOOSTMASTER SHORT BLOCK+RACE-KING TOP END

The Boostmaster 396 is the ultimate Gen V LT short block for serious horsepower enthusiasts.
Designed from the ground up for power-adder applications, it begins with the formidable GM L8T iron block —
chosen not for tradition, but for its superior strength and rigidity under pressure.
Where aluminum falls short in boosted builds, iron stays true—retaining shape, ring seal, and cylinder integrity
even under extreme combustion loads.

To balance strength with performance, we developed a proprietary lightening program that removes 23 lbs of material from non-critical areas. This smart reduction helps offset the typical weight of an iron block, delivering the durability you expect with less of the weight you don’t. It’s strength without unnecessary compromise.

Inside, the Boostmaster 396 features a no-nonsense, high-performance rotating assembly:

• Callies Magnum 8ccw 3.700” Wet Sump Crankshaft – Precision-balanced for rigidity and strength
• Callies Ultra Enforcer I-Beam Rods – With ARP Ultra 7/16” bolts for bulletproof reliability
• Diamond/GPI Custom 2K Forged Pistons – 4.125” bore, .200” valve pockets, 10cc dish for boosted resilience
• Trend H-13 .927” Tool Steel Wrist Pins – Built to take the heat and high load

Boostmaster 396 Advantages:

• Class-leading stroke/bore ratio for airflow and combustion efficiency
• Reduced cylinder and main journal distortion under high boost
• Superior head gasket seal integrity under extreme conditions
• Stable oil clearances in the cam/main journals and lifter bores
• Exclusive lightening program for iron-block performance without the weight

The Boostmaster 396 is your answer when sleeved aluminum blocks just can’t cut it.
Delivering unrivaled strength, consistent performance, and real-world durability, it’s the
smart choice for high-boost Gen V LT builds —without breaking the bank.
Push your build past the limit. Choose Boostmaster.

RACE KING LONG BLOCK!

STARTING WITH THE GPI SHORT BLOCK

Race-King Cylinder heads

Track attack Camshaft

ARP Studded

CHE Trunnion rockers

BTR chromoly pushrods

PSI springs

CHE bronze guides

KATECH ported

Timing setup options

GPI, Race-King and BTR Camshaft options

LT GRUDGE BOSS

OPTIONAL LONG BLOCK CRYO TREATMENT +$2874

OPTIONAL COMPLETE ENGINE CERAKOTE INCLUDING CERAKOTE CHAMBERS AND CERAKOTE CYLINDER HEADS/BLOCK +$1879