<VV> EXHAUST - 140 Logs & Tubes?

[Mark Durham]

Dale, any time you can free up the exhaust side of things it allows for more
volumetric efficiency of the engine as a whole and will allow it to produce
more power and it should effect all areas of the power curve to some extent.

That, simply put, is how todays 4 cylinder engine put out the amount of
power older 6 cylinder engines do. That's why EFI works so well, it
optimizes fuel delivery. DIS optimizes the spark delivery, and proper design
of intake and exhaust systems optimize air flow. Any of these
improvements allows the same number of cubic inches to produce more power
across the rpm range.

regards  Mark Durham



On Sun, Jul 18, 2010 at 8:05 PM, Dale Dewald <dkdewald at pasty.net> wrote:

> At 12:00 7/17/2010 -0400, tim colson wrote:
>
> >i run 140 exhaust manifolds on all of my motors. all of them are 164 cu
> >inch.   i use the smaller gaskets for better sealing. ( yes i have used /
> >tried  both sizes ) >>snip<<
>
> Tim, I assume that these are all engines with 95 & 110 heads and contain
> more or less stock camshafts.  Apparently you have noticed at least a
> qualitative improvement in performance.  You have also fitted dual
> exhaust/mufflers to all these engines and have found that they run better
> with about one size larger jet in the carburetors.
>
> To the Rest of the Group:
>
> 1) Has anyone gone farther than installing 140 exhaust logs on a 95 or 110
> hp engine?
> 2) Would there be "reasonable" benefit from installing 140 exhaust tubes in
> a 110 head?
> 3) Does "freeing up" the exhaust side of the 110 head improve power at low
> RPM, high RPM, both, or not at all?
> 4) What other parts should be considered with these exhaust modifications?
>
> Dale Dewald
> Hancock, MI
>
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