LPFIDI Carburetor Adapter Kit — 3/4" Aluminum Spacer for Holley/Carter 4‑Barrel to Quadrajet Spread‑Bore, Open‑Center Gaskets & Ha

LPFIDI's 3/4" aluminum carburetor adapter kit lets you bolt a 4-barrel square-bore carburetor (Holley or Carter/AFB) to a Quadrajet spread-bore intake — or reverse-fit it by flipping the spacer.

This precision-cast aluminum adapter spacer bridges the geometry difference between square-bore and spread-bore 4-barrel carburetors and intake manifolds. At 3/4" thick with an open-center design, the spacer preserves airflow while providing a secure mounting surface. The kit ships with two gaskets and all required hardware, so you get a complete, compact solution for common retrofits and carb swaps.

How does this adapter match different carburetor types?

The adapter is machined to accept standard square-bore bolt patterns (used by many Holley and Carter/AFB carbs) on one face and the Quadrajet spread-bore flange pattern on the other. You can bolt a square-bore carb onto a spread-bore intake, or flip the adapter to mount a spread-bore carb to a square-bore manifold.

• Cast aluminum body for accurate bolt alignment and repeatable sealing.
• Open-center shape keeps throttle bores clear for airflow continuity.
• Flippable design supports both square-to-spread and spread-to-square installations.

Will the 3/4" thickness affect manifold clearance or carb tuning?

The spacer height is a fixed 3/4" and typically provides modest additional clearance under the carburetor without dramatically changing signal characteristics. Because the center is open, airflow disruption is minimized, though any spacer can slightly alter calibration, so verify jetting after installation.

• 3/4" height for increased clearance and minor plenum volume change.
• Open center to reduce turbulence compared with solid spacers.
• Recommended: check baseplate-to-carb clearances and retune if necessary.

What comes in the kit and what tools do I need?

The package contains one cast aluminum adapter, two gaskets for proper sealing, and the hardware needed to fasten the assembly. No printed instructions are included, so basic hand tools and standard torque practices are required for a safe installation.

• 1 × cast aluminum adapter (3/4" open-center style).
• 2 × gaskets to prevent vacuum and fluid leaks.
• Complete set of mounting bolts and washers as pictured; use common hand tools and a torque wrench.

Who this is for: This LPFIDI adapter kit is targeted at classic-car restorers, hot-rodders, and DIY mechanics who need a reliable, reversible way to mate square-bore 4-barrel carburetors (Holley or Carter/AFB) with Quadrajet spread-bore intake manifolds. It's ideal when you want a sturdy aluminum spacer that maintains airflow with an open center, includes gaskets and fasteners, and gives the flexibility to flip the adapter for the opposite conversion. If you prefer bolt-on simplicity and don’t require a hand-hold installation guide, this compact kit covers the essential components for most conversions and swaps.