This is a basic 4bbl carburetor based on a 460 CFM Impco 425 mixer and square-bore 4bbl throttle body.  It can be installed on a spread-bore intake manifold with a square-bore to spread-bore adapter.  You assemble this carburetor from the following components:

• 1 x Impco CT425M-2 Model 425 Mixer, Silicone
• 1 x Gann TB9-8 Throttle Body, Holley Square Bore
• 1 x Gann 88EN Vapour Elbow, Nylon, 1" Hose x 1" MNPT

To make an underhood conversion kit, you must add either the BCP-EE or the BCP-EV Basic Components kits.  To mount this carburetor on a stock spread-bore Quadrajet or Thermo-Quad intake manifold, we recommend the Edelbrock PN 2696 or equivalent carburetor adapter.

Propane carburetors are not oversized like gasoline carburetors.  This carburetor will properly meter fuel to a 350 CID (5.7L) engine up to 5344 RPM.  On a 454 CID (7.4L) engine, this carburetor is good to 4120 RPM.  Above these RPMS, these engines will simply gradually lose power.  For stock V8 engine applications, this carburetor will work well.

For open-loop engine applications above 390 CID (or for generally better fuel economy), we recommend replacing the air-gas valve with PN AV1-1644-2.