David Vizard bench flows a BBD 2bbl
In the discussion about the pistons they mentioned “if we can get a light enough piston”.
Of course, they’re supposed to be using only stock replacement type parts.
There aren’t going to be any “light weight” stock replacement pistons.
They should all weigh about the same as the factory piece.
He should have better explained why he was testing the carb “as a 4bbl”.
4bbls are rated at 1.5”hg test pressure.
2bbls are rated at 3.0”hg test pressure.
I agree with them using the 4bbl test pressure, so the flow number for that 2bbl is directly comparable to a 4bbl(the numbers most are familiar with).
Keep in mind the number they got is “dry flow”.
Typically, the wet flow of a carb will be about 92% of the dry flow.