Good pick for a Holley on the GM spreadbore stock manifold is a 9895. Very tuneable and will pass emissions when set up correctly.
This carb has vacuum operated secondaries for smooth transition on a street truck. It also has an electric choke and ports for all the emissions. Brackets are available for auto transmissions, 700R4 or TH350C if needed.
Holley used to make spreadbore 650 CFM carbs that were model specific, but since these trucks are all 30 plus years old there are less specific choices.
Holley 9895 (click)
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