I have modified the stock Rochester end carbs to enlarge the venturi from 1.310" to 1.437" (1 7/16"). This is the limit of enlarging the stock end carbs--anything larger would require epoxy or a replacement insert for the venturi area.
The same is true of the large center Rochester carb. There are 2G carbs that have venturi sizes up to 1 3/8", but they are not easy to find. But, they can be modified to enlarge the venturi area as I have done with end carbs.
Some of you may remember the '65 GTO Glory Days. In the 1980's, that car ran low 10's with a '66 Tri-Power that had STOCK VENTURI sizes.. The manifold was ported to match the 722 RAIV heads and the area below the carbs. The entire heat riser passage and the water crossover has been removed. I have this manifold in my shop if you need any photos.
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BONESTOCK GOATS
'64 GTO Tripower Hardtop (Wife's Car)
'64 GTO Tripower Post Coupe (My Car)
'99 Bonneville SE Sedan
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