For LS Cathedral Port Cylinder Head to Rectangle Port Intake Manifold Adapters

Intake Manifold Adapter for LS Cathedral Port Cylinder Head to Rectangle Port

This adapter plate lets a rectangle port intake manifold bolt onto LS cathedral port cylinder heads, solving the mismatch between port shapes in a build.

Overview

This LS cathedral port to rectangle port intake manifold adapter is made for engine builders mixing cylinder heads and intakes from different LS generations. It bridges the port shape difference so an rectangular port manifold can sit on cathedral port heads without machine work. The adapter is a practical fix for anyone assembling a hybrid LS combination on a budget.

Built For Performance

• Converts cathedral port cylinder head flanges to accept rectangle port intake manifolds
• Aluminum construction for light weight and heat resistance
• Precision bolt pattern to line up with LS head and intake bolt holes
• Port shaping that transitions between the two runner profiles
• Sold as a pair for both banks of the engine
• Gasket surface machined flat for a clean seal

Fits These Machines

• for LS cathedral port cylinder heads
• for rectangle port intake manifolds
• for LS1 and LS6 style head castings
• for LS3 and L92 style intake manifolds

On-The-Job Use

• Hybrid LS builds mixing heads and intakes from different generations
• Budget engine swaps where matching parts are not on hand
• Race car and truck engine assembly
• Test fitting intake options on a build stand

Specs At A Glance

Good To Know

Q: Will this adapter fit any LS engine? A: It is made for LS engines with cathedral port heads and rectangle port intake manifolds, not the reverse. Confirm both your head and intake port styles before ordering.

Q: Do I need special gaskets or bolts? A: You will typically need gaskets on both sides of the adapter and longer intake bolts to account for the added thickness. Check clearance to the hood and fuel rails after install.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.