Carburetion can be anything from a set of 2 Carter AFB's (high end) to a 15 year-old sitting on the hood and pouring gasoline into the engine out of a boot (low end???).

Most carburetors will fall in-between the above.

The e-clones are basically the Federal Mogul rework of the Carter aftermarket carburetors for Chevrolet engines.

To make the ORIGINAL Carter aftermarket Chevrolet carburetors work WELL on a Pontiac engine, the following is generally necessary:

idle circuit - generally OK for engines up to a mild 400. 455's may require machining of the idle tubes, restrictors, idle air bleeds, and idle bypass. These are all pressed-in items. Hot 400's may require some of the mods for 455.

primary circuit - any Pontiac engine, different profile metering rods. jets may require changing, but jets are readily available. Vacuum pistons springs (again readily available) may need to be changed (the camshaft profile will determine this issue).

secondary circuit - jetting will require changing (again, jets are readily available). Hot 400's and 455's will REQUIRE a DIFFERENT auxillary air valve (an older Pontiac AFB makes a good donor, and one may also be able to use the metering rods). Failure to change the air valve will pretty much guarantee a hesitation when hitting the secondaries (hot 400's and 455's).

pump circuit - 455's may require modification, generally OK for 400's.

floats, fuel valves, etc. - probably no problems.

The original Carters (due to different production standards) seem to be much less problematic than the later Federal Mogul produced Carters.

Nashville - please do not send peanuts! I love em, but they are no longer on my diet.

Jon.