[Dick Boneske]

There are many large 2G carbs that function well as a substitute for the correct 7031575 float bowl and 7031587 airhorn.

Differences on most of these clones include:
*Usually no idle vent
*Added air channels under the venturi cluster. ('68 and newer)
*Added brass tube adjacent to the power valve rod (about '69 and newer)
*The use of phenolic floats vs. brass (all after '67). .
*Differences in the throttle body with choke, vacuum nipples, and provision for ported vacuum

.I have used clone center carbs for '66 Tri-Powers. Some owners want larger venturi openings vs. the correct '66 that has 1.180". I have used clones that are as large as 1.315" for slightly more cfm

I have not found an explanation for the added air channels under the venturi cluster, nor the purpose of the added brass tube next to the power valve rod.

The differences in the throttle bodies is normally not an issue--sometimes a bonus if the customer needs an additional vacuum source.

I would appreciate it if someone more knowledgeable than I would explain the added air channels and the single added brass tube.