LS3 Block & Heads

A dimensionally correct LS3 block and heads you can print and hold. Mock the swap on the bench instead of in the car. Build headers around a printed engine at 2am without a hoist, a crane or a bare block sitting in your bay for six weeks.

The steel mock-up block that does this job sells for $309. There are free LS3 models floating around — they are render meshes. They are not watertight, not to print tolerance, and the mounting geometry is decorative. This one is built to be printed and measured against.

What you download

• STEP — native solid, so you can bolt your own parts to it in Fusion, SolidWorks or Onshape
• STL — watertight, print-ready
• Correct deck height, bore spacing, bellhousing pattern, motor mount and accessory locations
• Sectioned to fit a 256mm bed
• Instant download at checkout. Nothing ships.

What people use it for

Header and manifold design without the engine present · engine bay fitment before you buy the swap · checking accessory clearance · CAD reference for a part you're drawing · a shop display that doesn't weigh 400 pounds.

Licence — Shop Use

Print as many copies as you like for use in your own shop, including on paying customer jobs and in design work you're paid for. You may not share or resell the file itself. Print-and-sell licences available — ask.

Drawn by James Goertz, G1Pro. I built this model because I needed it to design manifolds — it's the same file I work from.