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| Re: [GMCnet] 455 Engine [message #121632 is a reply to message #121629] |
Tue, 12 April 2011 17:48   |
k2gkk
Messages: 4452
Registered: November 2009
Karma: -8
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Senior Member |
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As far as I know, the only REAL difference is the camshafts!
Displacement is still the same and camshaft lift, timing, and
duration are what make the difference.
I'm quite certain that there are folks here that have favorite
cam(s) for the torque required to make ANY 455 do the job for
a GMC motorhome!
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ex-Palm Beach, 76 ~ ~ ~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
> To: gmclist@temp.gmcnet.org
> From: j.galbavy@att.net
> Date: Tue, 12 Apr 2011 17:11:19 -0500
> Subject: Re: [GMCnet] 455 Engine
>
>
>
> Would possibly make a good core block since the guts are for a high rpm / low torque car. ....not a low rpm / high torque motorhome.
>
> jim galbavy
> '73 x-CL ANNIE
> Chesterfield, Va // LAKE MARY, FL
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| Re: [GMCnet] 455 Engine [message #121649 is a reply to message #121629] |
Tue, 12 April 2011 21:07 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Jim, in my personal experience, an engine that has an undersquare design,
stroke being longer than the bore, with the camshaft advanced 4 degrees over
straight up, will produce torque at a lower rpm. An oversquare design like
the 403 Olds, with the bore larger than the stroke, same cam timing, tends
to produce it's max torque at a slightly higer rpm. There are many more
variables than this, like compression ratio, valve sizes and port designs
along with header tubing diameter & length, intake manifold design and carb
venturi sizes & the list goes on. Plusses might include 4 bolt main bearing
caps, forged pistons, stellite valve seats and stainless steel valves,
roller cams and rockers, trueroller timing chain set, this will generate
plenty of opinions + or -.
Jim Hupy
Salem, Or
78 GMC Royale 403
On Tue, Apr 12, 2011 at 3:11 PM, Jim Galbavy <j.galbavy@att.net> wrote:
>
>
> Would possibly make a good core block since the guts are for a high rpm /
> low torque car. ....not a low rpm / high torque motorhome.
>
> jim galbavy
> '73 x-CL ANNIE
> Chesterfield, Va // LAKE MARY, FL
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> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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