351 carbed problem

[tom cloud]

 dave.williams at chaos.lrk.ar.us (Dave Williams) wrote:

>-> Those carb formulas are nearly worthless.  A carb is a restriction in
>-> the induction path.  For performance use, you want the largest CFM
>-> rating that will still properly atomize the fuel.
>
> I disagree.  The usual carb sizing formalas work very well,
>particularly with primitive instruments such as Holleys.  I've often
>seen .1 or better in the 1/4 by dropping back from a 750 or 780 to a
>600, not to mention the improvement in street driving.

        [ snip ]

> For EFI stuff, the extra runner length and typical tiny throttle body
>have more pressure drop than even a "small" carburetor.

        [ snip s'more ]

I'd like to hear some more 'bout this.  I bought the Holley Pro-Jection
TBI and they say that unit has considerably less flow restriction
than a comparable carb and that the requirement to size the cfm to
the engine is relaxed for the EFI since the amount of fuel is
determined by the electronics rather than vacuum and air flow.
Is the above statement true for TPI and not TBI ??

Tom

Tom Cloud <cloud at peaches.ph.utexas>

None of the opinions expressed here are mine or anyone elses