You would need a bigger venturi, better airflow through the cylinder head and both manifolds, and a different grind on the camshaft. Putting one heavy duty link in a chain made of paperclips won't improve the strength of the chain. Updraft carbs in general don't lend themselves to high performance very well, and there's no room for any other style of fuel system on your truck, is there?
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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