Just to clarify:

The carbs pictured by Tom in post 1 of this thread from left to right:

Zenith single barrel
Holley two barrel
Holley single barrel

The carb pictured in post 2 by pdlightning is a Stromberg 2-barrel type WW.

As to what have might have been original; more information would be required. On different applications of the 270 in different years, G.M.C. used (in alphabetical order) Carter type W-1, Holley type 1904, and Zenith types 28, 30, 63, and 228.

All are single barrels

Jon

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