Part# 1033012 & 1033021 – Holley to Weber Pattern Manifold Adapter Kit (Not for Stock Manifold)

To open a printable PDF version of this instruction CLICK HERE

Since the Holley carburetor bores are so much larger than the manifold it is recommended to port match your manifold to our adapter for optimal performance. LC Engineering recommends pre installing the adapter up to your manifold to see where you will need to port match the manifold.

Kit Includes:

(1) Holley Carb. to Weber Manifold Adapter
(4) M8-1.25 x 35mm Hex Bolt
(4) M8-1.25 Nylock Nut Small Patt - Zinc
(4) M8 Wave Washer - Zinc
(4) 5/16-18 x 3/4 Allen Bolt
(1) Holley Base Gasket
(1) 20R/22R Weber Pattern Base Gasket


  1. Block off your EGR mount.(If it does not clear the Throttle Linkage you will need parts # 8010086 and # 1035087)
  2. Pre install the adapter onto your manifold (no gaskets). Inspect the manifold opening and port to match. Any port work should be done with the manifold off the engine. Make sure to clean the manifold thoroughly after porting. At this time cut the base gasket to accommodate to your new larger opening.
  3. Install the four M8x35mm Hex Bolts from the bottom of the adapter. The part number is engraved on top of the plate for reference.
  4. Lightly coat lower gasket with white lithium grease on both sides (to help seal better) and install onto your manifold. Set your new adapter on top of the gasket.
  5. Install adapter on intake manifold using the supplied allen bolts to attach adapter to manifold(Lock-tight can be used).
  6. Lightly coat carburetor gasket with white lithium grease on both sides. Install your carburetor onto the adapter and use wave washers and nuts to tighten down. (DO NOT EVER TIGHTEN, IT WILL DAMAGE THE CARB. BASE)