BluePrint BP4002CTC1 GM 400, Base Dressed Engine, Alum Heads, Roller Cam

Take the 400-cubic-inch base engine above and add induction: this dressed version carries the same 500-horsepower, 510-pound-foot output on 10.3:1 compression, now with an 850-cfm Holley carburetor and a manual choke already mounted to a dual-plane intake.

What the dress adds

The 850-cfm Holley carburetor rides a dual-plane, satin aluminum manifold and fires through an installed distributor. Freeze plugs are brass, the timing cover and oil pan close out the bottom, and valve covers cap the heads. BluePrint's dyno sheet, the same kind of paperwork included across its longblocks, ships with every engine before it leaves the shop.

Bottom end and heads

The casting is square and parallel decked, sonic tested for wall thickness, and bored on equipment holding straightness and roundness to .0002 inch, with a one-piece rear seal added over the bare version. A forged crankshaft turning 5.7-inch rods, their bolts rated to 150,000 psi, carries forged pistons balanced to within 2 grams, under aluminum heads using 1.6 roller rockers. Not designed for EGR compatibility; this build carries the same coverage term as BluePrint's other 400-based longblock, 30 months or 50,000 miles.

What's the difference from the Base Engine listing? This one adds the carburetor, intake manifold, and distributor up front; the Base Engine ships without any of them installed, leaving induction to the builder.