Rochester 'Small' 2GC to Motorcraft/Holley 2bbl Carburetor Adapter
Finally, a legacy grade solution for adapting a Motorcraft/Holley 2bbl carb to your 2gc (small ) Rochester intake on engines like the legendary Buick 225 Odd-fire and others. This adapter was designed to solve many of the current issues with the cheap cast aluminum adapters common in the market.
These adapters are precision CNC machined from a solid bars of 6061-T6 billet aluminum. They are 1/2" thick to help with under-hood clearance as much as possible, but many times stronger than any cheap cast aluminum part. The Motorcraft/Holley side of the adapter uses a hex shaped insert to allow a one tool install in tight under-hood spaces and provide for fully replaceable threads/nuts available at any hardware store in an emergency. The mounting bolts can also be flipped to form a 'stud' type mount if you prefer.
The adapter is designed around the 'small' Rochester bolt pattern on the engine side. That pattern measures 3.25" side to side and 1.87" front to back. It is symmetrical with a ~1.45" bore size on the manifold. The Motorcraft side is designed around a 1.08 or 1.14 version with a ~1.56 bore. The bores are CNC machined to be taper port matched to help low end throttle response and high speed air flow. This also provides a stronger more reliable vacuum signal at the carb base. The adapter can be hand ported to match other size throttle bores. This unit will also allow the use of the 'deep' 2 stage power valve cover on most Motorcraft 2bbl Carburetors, including the new reproduction 1.14 2150 units being sold now.
This adapter includes all the required mounting hardware and an extra-large, extra-thick 1/16" base gasket for the Rochester side. This gasket will help deal with any irregularities in the stock intake mounting surface after nearly 50+ years of service. The carburetor side mounting bolts are fine thread units with a nylon locking nut.
It is recommended that the heat riser ports in the factory intake be completely blocked off with press in small metal plug. The exhaust gases from these ports commonly cause failures in the base gasket and pitting of the intake manifold sealing surface.
If your stock intake manifold is heavily pitted, it is recommended that it be decked clean or filled with epoxy to provide the best sealing surface possible.
Do not over-tighten the carburetor side mounting bolts. This will cause the ears, with the broad Motorcraft/Holley bolt pattern, to bend. This is the main cause of leaks on the carburetor side of the adapter.
If you are using a deep pump cover for a 2-stage power valve, you will need to use a thick insulating gasket between the carb and adapter. The factory Jeep 2bbl intake will also need to be lightly ground for clearance in the thermostat housing area.
USPS flat rate shipping is included