Picking the Right Camshaft Nets Us 28 Hidden Horsepower on the Dyno

BPE GM 364LS: A Powerful 6.0L + LS3 Head Hybrid
When it comes to popular LS engine combinations, adding a set of rectangular port LS3 heads to a 6.0L iron block is tough to beat. This setup provides the durability of an iron block with a 4.000-inch bore that can accept high-flow LS3 heads. (Note: LS7 heads are not recommended due to their design around a 4.125-inch bore.)

The LS3 heads flow nearly 70 CFM better than the cathedral-port heads that originally came with the 6.0L, explaining the appeal of this hybrid. However, building this combo requires sourcing both a 6.0L short-block and LS3 components like the heads, rockers, pushrods, and a rectangular port intake manifold — a task easier if you already have one major part.

To simplify the process, BluePrint Engines (BPE) offers a complete hybrid long-block — the BPE GM 364LS — combining the strength of the 6.0L block with LS3 heads.

BPE GM 364LS Long-Block Highlights
Iron block

Forged pistons

9.8:1 static compression ratio

Factory GM crank (24X crank trigger)

Rear cam sensor

BPE rectangular port aluminum LS3 heads (PN PS8015)

259cc intake ports

102cc exhaust ports

72cc combustion chambers

2.165" intake valves

1.600" exhaust valves

12° valve angle

Single-pattern performance cam

0.556" lift

223° duration

114° LSA

Adjustable timing chain and oil pump included

Initial Dyno Test Setup
BPE reported the long-block produced 470+ hp and 455+ lb-ft of torque with a factory GM LS3 intake and 90mm throttle body.

For testing, a carbureted setup was used instead, including:

Dual-plane Holley intake

950-cfm Holley Ultra XP carburetor

Louvered windage tray (Improved Racing)

GM C6 oil pan

MSD ignition controller for precise timing

Lucas break-in oil, followed by Lucas 5W-30 synthetic

With total timing set at 31 degrees, the engine produced:

494 hp @ 6,200 rpm

457 lb-ft @ 4,400 rpm

Camshaft Upgrade & Power Gains
To push further, a Comp Cams 277LRR grind was installed:

0.614"/0.624" lift

227°/243° duration

113° LSA

The result:

522 hp @ 6,500 rpm

463 lb-ft @ 4,200 rpm

This cam delivered more power across the entire RPM range, proving to be an excellent upgrade for the BPE 6.0L crate engine.