BluePrint PSLS4270CTC Pro LS 427 625 HP Carb Retrofit LB Long Block Crate Engine

Description

Featuring 625 naturally aspirated horsepower, the BluePrint PSLS4270CTC Pro Series Crate Engine merges modern LS valvetrain design with simple four barrel carburetion. Displacing 427 cubic inches from a 7.0 liter platform, this dressed long block outputs 565 lb-ft torque at 4800 RPM. A single plane intake and standalone ignition controller make this motor a top tier candidate for vintage conversions.

An aftermarket cast iron LS block features deep skirt architecture anchored by six bolt cross bolted main caps. Rotating parts include a 4340 forged steel 4.000 inch stroke crankshaft, forged 6.125 inch H-beam connecting rods, and forged aluminum pistons inside 4.125 inch bores. The 11.0:1 compression ratio runs on 93 octane pump fuel. Sump capacity measures six quarts, bringing dry weight to 475 lbs.

Key Features of BluePrint PSLS4270CTC

Buy BluePrint PSLS4270CTC crate engine configurations to combine modern LS engine architecture with simple carburetor tuning. The dressed package pairs high flow rectangular port aluminum cylinder heads with a tuned four barrel carburetor for immediate track readiness.

• 850 CFM four barrel electric choke carburetor meters high air volume for unrestricted high RPM power.
• Single plane open plenum aluminum intake manifold supplies unrestricted air volume to cylinders above 3500 RPM.
• LS7 style rectangular port aluminum cylinder heads flow massive intake air volume past 6500 RPM.
• Stroker 4.000 inch forged crankshaft produces 565 lb-ft torque to launch heavy vehicle chassis hard.
• Standalone ignition control module fires individual coil packs using crank sensor position inputs.
• BluePrint PSLS4270CTC valvetrain components feature full roller rocker arms to minimize friction.
• Six bolt cross bolted iron main caps eliminate crank journal flex under elevated track RPM loads.

Carbureted LS 427 Dyno Output

Testing on water brake engine dynamometers validates 625 brake horsepower at 6300 RPM and 565 lb-ft torque at 4800 RPM across a wide 2500 to 6600 RPM band. Camshaft events measure 238 degrees intake and 246 degrees exhaust duration at 0.050 inch lift, producing 0.620 inch intake and 0.620 inch exhaust lift. The engine draws 12 in-Hg vacuum at 900 RPM on 93 octane fuel, holding 50 to 65 PSI hot oil pressure.

Retrofit Oil Pan Crossmember Fitment

Standard GM LS architecture drops between subframe rails on vintage Camaro, Chevelle, and C10 chassis when paired with swap engine mount plates. The crankshaft accepts 4L60E, 4L80E, or manual transmission bellhousings using standard LS flexplates or flywheels. Low profile intake components clear factory hood lines, while the retrofit oil pan clears intermediate steering linkages.

Carbureted LS Startup Protection Rules

Pressurize the engine oiling channels with a pre lube tank prior to turning the starter key to safeguard crank and cam bearings. This competition crate engine is not engineered for marine bilge setups, forced induction boost exceeding six PSI on stock ring end gaps, or unmetered nitrous oxide systems.

• Drain break in oil and replace the spin on lube filter after the first 500 operating miles.
• Perform regular motor oil changes every 3000 miles or six months with high zinc synthetic oil.
• Inspect carburetor float adjustments and verify ignition timing advance every 6000 street miles.

Carbureted Retrofit Crate Manifest Warranty

Protection includes a 30-Month / 50,000-Mile factory limited warranty guarding against defective components. The shipment crate contains the dressed long block, 850 CFM carburetor, single plane intake manifold, standalone ignition box, coil packs, spark wires, oil pan, valve covers, and an official dynamometer run sheet.