> When heads and manifolds are flowed, you can use any pressure you want. I
> use 7" because it makes the math easier, and also because of the max
> capabilities of my flow bench vacuum source. However, to compare to
> readings taken by other flow benches or on other products, there
> must be a
> common standard vacuum for comparison purposes. The 'industry'
> has settled
> on 28" of water.
Thanks, Jack, Ron & others who responded.
28" still seems high to me, after all that's roughly 1/10 of the total
pressure you have to stuff air into the cylinders, and there's still the
drop through the carbs and valves to consider. I guess the industry is
mostly interested in big numbers and, as usual, doesn't care if those
numbers actually mean anything.
Randall
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