Re: [omc-boats] Re: omc-boats-digest V1 #581

SAE ratings for autos did change from gross vs net and the lean running
emissions controls started taking their tolls as well into the mid
seventies. Finally catalytic converters O2 sensensors helped restore some of
the power.

But the ratings and measurement for marine engines didn't reflect these
changes, as far as I know.

It's just speculation on my part but I'd bet a picther of beer that electric
stringer hp ratings had more to do with sales and marketing and competing
head-to-head with MerCruiser, than anything resembling scientific
measurement. And remember these changes only occured on the 307-based Chevy.
When the V6 Buick was upped 5 hp between 66 and 67 models from 150 to 155
there were bonafide changes in carbs and intake manifolds. But none of the
other engines' hp ratings ever changed. I think Ford made OMC a deal they
couldn't refuse and essentially bought their way into replacing the 307
Chevy at OMC. I also think GM couldn't make enough 350's for cars and trucks
so they probably priced Marine versions beyond the excellent 351W and Ford's
bread and butter 302's. Wierd thing is why did the Ford 302 only make 175
and 190 hp when the Chevy 307 is 210-215-225. There just shouldn't be that
much difference in my mind.

So if you want to get me to buy you that pitcher of beer-- find me the part
number changes between a 1970 210-hp and a 1971 215-hp or a 1972 225-hp.

I'd personally like to hear from anyone that's transpalnted a 350,
383-stroker or 400 small block. I've heard that once you go much beyond
250-hp and 4600 RPM the electric stringer tends to have avastly reduced
service life. I'd love to someday try a mildly tuned and cammed 400 SBC
with great idle and mucho torque. I think the economy would be impressive
and it would loaf along most of the time. I knew I guy that did it with a
800 Stringer and he really loved it.

Lee

----- Original Message -----
From: "Thomas Klauber" <tklauber@...>
To: <omc-boats-digest@...>
Sent: Tuesday, September 12, 2006 7:18 PM
Subject: [omc-boats] Re: omc-boats-digest V1 #581

> In 1971 the auto guys changed horsepower ratings to accomodate emissions
> etc on the new cars and that changed the HP ratings however the numbers
> went down, I think as they were reporting netHP with all things attached
> rather than raw HP as had been the previous. I remember some of this as I
> used to hang around Corvettes in the 70s and 80s. TK
> ----- Original Message -----
> From: "omc-boats-digest" <owner-omc-boats-digest@...>
> To: <omc-boats-digest@...>
> Sent: Tuesday, September 12, 2006 12:00 PM
> Subject: omc-boats-digest V1 #581
>
>
>>
>> omc-boats-digest Tuesday, September 12 2006 Volume 01 : Number
>> 581
>>
>>
>>
>> [omc-boats] Through Transom Exhaust
>> [omc-boats] venting the cowling
>> RE: [omc-boats] venting the cowling
>> Re: [omc-boats] venting the cowling
>> Re: [omc-boats] Through Transom Exhaust
>> RE: [omc-boats] venting the cowling
>> Re: [omc-boats] venting the cowling
>>
>> ----------------------------------------------------------------------
>>
>> Date: Mon, 11 Sep 2006 23:08:58 -0700
>> From: "Scott E. Veazie" <scottveazie@...>
>> Subject: [omc-boats] Through Transom Exhaust
>>
>> Would there be a horsepower increase by changing the exhaust from the
>> stern
>> drive to a through transom setup? I've always wondered this, besides the
>> "muscle sound" gained going this route.
>>
>> ~Scott
>>
>> - -----
>> To get off this list send mail to omc-boats-unsubscribe@...
>>
>> ------------------------------
>>
>> Date: Mon, 11 Sep 2006 23:39:46 -0700
>> From: "jdood" <jdood@...>
>> Subject: [omc-boats] venting the cowling
>>
>> I have a 65 omc deluxe i/o that I know little about. I have been
>> finding that it seems to be running better without the cowling on the
>> engine. Perhaps my imagination, but I don't think so. So did those
>> cowlings ever have vents in that nice flat section of the front that
>> seems perfect for a vent grill? Would I be screwing anything up to put
>> one in there? Those little grills in the back seem kind of useless.
>>
>> Thanks for any comments!
>>
>> jeff
>>
>> - --
>> No virus found in this outgoing message.
>> Checked by AVG Free Edition.
>> Version: 7.1.405 / Virus Database: 268.12.3/444 - Release Date:
>> 9/11/2006
>>
>>
>> - -----
>> To get off this list send mail to omc-boats-unsubscribe@...
>>
>> ------------------------------
>>
>> Date: Tue, 12 Sep 2006 06:26:42 -0600
>> From: "knight" <knight@...>
>> Subject: RE: [omc-boats] venting the cowling
>>
>> I have a 69 rogue that is currently running at 6000 to 7000 feet above
>> sea
>> level. I completely built a taller cowling with plenty of vent screen.
>> It defiantly runs better with all the air I can get to it. Try turning on
>> your bilge blower and see if that helps too. Joe.
>>
>> - -----Original Message-----
>> From: owner-omc-boats@... [mailto:owner-omc-boats@...]
>> On
>> Behalf Of jdood
>> Sent: Tuesday, September 12, 2006 12:40 AM
>> To: omc-boats@...
>> Subject: [omc-boats] venting the cowling
>>
>>
>>
>> I have a 65 omc deluxe i/o that I know little about. I have been
>> finding that it seems to be running better without the cowling on the
>> engine. Perhaps my imagination, but I don't think so. So did those
>> cowlings ever have vents in that nice flat section of the front that
>> seems perfect for a vent grill? Would I be screwing anything up to put
>> one in there? Those little grills in the back seem kind of useless.
>>
>> Thanks for any comments!
>>
>> jeff
>>
>> - --
>> No virus found in this outgoing message.
>> Checked by AVG Free Edition.
>> Version: 7.1.405 / Virus Database: 268.12.3/444 - Release Date:
>> 9/11/2006
>>
>>
>> - -----
>> To get off this list send mail to omc-boats-unsubscribe@...
>>
>> - -----
>> To get off this list send mail to omc-boats-unsubscribe@...
>>
>> ------------------------------
>>
>> Date: Tue, 12 Sep 2006 08:20:56 -0500
>> From: David <odin@...>
>> Subject: Re: [omc-boats] venting the cowling
>>
>> It wouldn't hurt anything to put a vent in - but I think I would put it
>> on the port side of the cowling - where the carb is located since you
>> wouldn't see it there - Dave
>>
>> jdood wrote:
>>
>>> I have a 65 omc deluxe i/o that I know little about. I have been
>>>finding that it seems to be running better without the cowling on the
>>>engine. Perhaps my imagination, but I don't think so. So did those
>>>cowlings ever have vents in that nice flat section of the front that
>>>seems perfect for a vent grill? Would I be screwing anything up to put
>>>one in there? Those little grills in the back seem kind of useless.
>>>
>>>Thanks for any comments!
>>>
>>>jeff
>>>
>>>
>>>
>> - -----
>> To get off this list send mail to omc-boats-unsubscribe@...
>>
>> ------------------------------
>>
>> Date: Tue, 12 Sep 2006 08:34:42 -0600
>> From: <lib1@...>
>> Subject: Re: [omc-boats] Through Transom Exhaust
>>
>> Another good question that actually has some historical background.
>>
>> Just after OMC quit building our boats and sold the molds and rights to
>> Chris Craft in 1970-71 they increased the rated power of their small
>> block
>> 307 Chevy V8.
>>
>> In the 19-footer E/J's that OMC built the 307 was rated at 210 hp. This
>> was
>> in models years 1969-1970.
>>
>> In 1971 they bumped the 210 to 215 and as far as I can tell from
>> researching
>> parts manuals no parts were changed in the process. Perhaps someone in
>> engineering got a better dynomometer, who knows?
>>
>> But in 1971, they also introduced a 235 hp 307 Chevy. (Not to be confused
>> with the later Ford-based 235 hp electric stringer). These 235 hp Chevies
>> were painted red (as opposed to gray) and had Corvette/Camaro Z-28 cast
>> aluminum valve covers. Theses engines also had the more agressive
>> Corvette
>> camshafts and THRU-THE-TRANSOM exhausts. They didn't idle down as well as
>> the 210-215's but they sure do sound cool (or annoying depending on your
>> point of view)! Not a lot were sold but you see them in the early
>> Pachanga's
>> (a Donzi-like v-hull boat).
>>
>> The in 1972 -74 OMC upped ante again and moved the 215 to 225. The
>> "Corvette-Based" 235 jumped to 245. The engines were built to OMC's
>> spec's
>> by Chevy as they never offered a 307 in their car or truck lines with the
>> QuadraJet and the hot Corvette camshaft. The OMC shifted focus to 302 and
>> 351 Fords and the short-shaft stringer and Chevy 307 was phased out.
>> There
>> are more 225/245's out there than 215/235's becuase they were made for a
>> couple years longer. As far as I can tell 210-215-225's are all the carb,
>> cams, and heads. An the same applies to the 235/245's which are
>> indentical
>> twins as well.
>>
>> My advice (and this is based on talking to experienced OMC mechanics) is
>> to
>> leave well enough alone. About all you will accomplish in changing the
>> exhaust is a lot more sound, er noise. You may think you're going faster
>> but
>> the power gains will practically un-detectable. That's because they
>> engineered the back-pressure and matched it verywell to the 210-215-225's
>> exhaust manifolds and camshaft. A hotter cammed 290-hp 350 might need
>> less
>> back pressure, but not our engines. Even the thru-hub exhaust of the
>> 400-800
>> stringer probably didn't add more than fractional horsepower gains.
>>
>> Probably more than you really cared to know......
>>
>> Lee Shuster
>> Salt Lake City
>>
>> - ----- Original Message -----
>> From: "Scott E. Veazie" <scottveazie@...>
>> To: <omc-boats@...>
>> Sent: Tuesday, September 12, 2006 12:08 AM
>> Subject: [omc-boats] Through Transom Exhaust
>>
>>
>>> Would there be a horsepower increase by changing the exhaust from the
>>> stern drive to a through transom setup? I've always wondered this,
>>> besides the "muscle sound" gained going this route.
>>>
>>> ~Scott
>>> -----
>>> To get off this list send mail to omc-boats-unsubscribe@...
>>>
>>
>> - -----
>> To get off this list send mail to omc-boats-unsubscribe@...
>>
>> ------------------------------
>>
>> Date: Tue, 12 Sep 2006 08:32:23 -0700
>> From: "jdood" <jdood@...>
>> Subject: RE: [omc-boats] venting the cowling
>>
>> So if the engine runs better with vents, now I am wondering why they
>> didn't put them in originally? Noise? Or is there some special
>> marine/safety issue with venting it?
>>
>> - -----Original Message-----
>> From: owner-omc-boats@... [mailto:owner-omc-boats@...]
>> On Behalf Of David
>> Sent: Tuesday, September 12, 2006 6:21 AM
>> To: omc-boats@...
>> Subject: Re: [omc-boats] venting the cowling
>>
>> It wouldn't hurt anything to put a vent in - but I think I would put it
>> on the port side of the cowling - where the carb is located since you
>> wouldn't see it there - Dave
>>
>> jdood wrote:
>>
>>> I have a 65 omc deluxe i/o that I know little about. I have been
>>>finding that it seems to be running better without the cowling on the
>>>engine. Perhaps my imagination, but I don't think so. So did those
>>>cowlings ever have vents in that nice flat section of the front that
>>>seems perfect for a vent grill? Would I be screwing anything up to put
>>>one in there? Those little grills in the back seem kind of useless.
>>>
>>>Thanks for any comments!
>>>
>>>jeff
>>>
>>>
>>>
>> - -----
>> To get off this list send mail to omc-boats-unsubscribe@...
>>
>> - --
>> No virus found in this incoming message.
>> Checked by AVG Free Edition.
>> Version: 7.1.405 / Virus Database: 268.12.3/444 - Release Date:
>> 9/11/2006
>>
>>
>> - --
>> No virus found in this outgoing message.
>> Checked by AVG Free Edition.
>> Version: 7.1.405 / Virus Database: 268.12.3/444 - Release Date:
>> 9/11/2006
>>
>>
>> - -----
>> To get off this list send mail to omc-boats-unsubscribe@...
>>
>> ------------------------------
>>
>> Date: Tue, 12 Sep 2006 10:57:02 -0500
>> From: David <odin@...>
>> Subject: Re: [omc-boats] venting the cowling
>>
>> This is a multi-part message in MIME format.
>> - --------------070905040703020903050202
>> Content-Type: text/plain; charset=us-ascii; format=flowed
>> Content-Transfer-Encoding: 7bit
>>
>> Probably never noticed it - during my stint in engineering at OMC I ran
>> a lot of hours testing on Lake Michigan - there were several other OMC's
>> out on endurance that ran everyday - I do not recall ever seeing anyone
>> run with the engine cover off - so it is likely no one ever had the
>> chance to notice the difference - Dave
>>
>> jdood wrote:
>>
>>>So if the engine runs better with vents, now I am wondering why they
>>>didn't put them in originally? Noise? Or is there some special
>>>marine/safety issue with venting it?
>>>
>>>-----Original Message-----
>>>From: owner-omc-boats@... [mailto:owner-omc-boats@...]
>>>On Behalf Of David
>>>Sent: Tuesday, September 12, 2006 6:21 AM
>>>To: omc-boats@...
>>>Subject: Re: [omc-boats] venting the cowling
>>>
>>>It wouldn't hurt anything to put a vent in - but I think I would put it
>>>on the port side of the cowling - where the carb is located since you
>>>wouldn't see it there - Dave
>>>
>>>jdood wrote:
>>>
>>>
>>>
>>>>I have a 65 omc deluxe i/o that I know little about. I have been
>>>>finding that it seems to be running better without the cowling on the
>>>>engine. Perhaps my imagination, but I don't think so. So did those
>>>>cowlings ever have vents in that nice flat section of the front that
>>>>seems perfect for a vent grill? Would I be screwing anything up to put
>>>>one in there? Those little grills in the back seem kind of useless.
>>>>
>>>>Thanks for any comments!
>>>>
>>>>jeff
>>>>
>>>>
>>>>
>>>>
>>>>
>>>-----
>>>To get off this list send mail to omc-boats-unsubscribe@...
>>>
>>>
>>>
>>
>> - --------------070905040703020903050202
>> Content-Type: text/html; charset=us-ascii
>> Content-Transfer-Encoding: 7bit
>>
>> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
>> <html>
>> <head>
>> <meta content="text/html;charset=windows-1250"
>> http-equiv="Content-Type">
>> <title></title>
>> </head>
>> <body bgcolor="#ffffff" text="#000000">
>> Probably never noticed it - during my stint in engineering at OMC I ran
>> a lot of hours testing on Lake Michigan - there were several other
>> OMC's out on endurance that ran everyday - I do not recall ever seeing
>> anyone run with the engine cover off - so it is likely no one ever had
>> the chance to notice the difference - Dave<br>
>> <br>
>> jdood wrote:<br>
>> <blockquote cite="mid017401c6d680$a56f2380$0a00a8c0@..." type="cite">
>> <pre wrap="">So if the engine runs better with vents, now I am wondering
>> why they
>> didn't put them in originally? Noise? Or is there some special
>> marine/safety issue with venting it?
>>
>> - -----Original Message-----
>> From: <a class="moz-txt-link-abbreviated"
>> href="mailto:owner-omc-boats@...">owner-omc-boats@...</a>
>> [<a class="moz-txt-link-freetext"
>> href="mailto:owner-omc-boats@...">mailto:owner-omc-boats@...</a>]
>> On Behalf Of David
>> Sent: Tuesday, September 12, 2006 6:21 AM
>> To: <a class="moz-txt-link-abbreviated"
>> href="mailto:omc-boats@...">omc-boats@...</a>
>> Subject: Re: [omc-boats] venting the cowling
>>
>> It wouldn't hurt anything to put a vent in - but I think I would put it
>> on the port side of the cowling - where the carb is located since you
>> wouldn't see it there - Dave
>>
>> jdood wrote:
>>
>> </pre>
>> <blockquote type="cite">
>> <pre wrap="">I have a 65 omc deluxe i/o that I know little about. I
>> have been
>> finding that it seems to be running better without the cowling on the
>> engine. Perhaps my imagination, but I don't think so. So did those
>> cowlings ever have vents in that nice flat section of the front that
>> seems perfect for a vent grill? Would I be screwing anything up to put
>> one in there? Those little grills in the back seem kind of useless.
>>
>> Thanks for any comments!
>>
>> jeff
>>
>>
>>
>> </pre>
>> </blockquote>
>> <pre wrap=""><!---->-----
>> To get off this list send mail to <a class="moz-txt-link-abbreviated"
>> href="mailto:omc-boats-unsubscribe@...">omc-boats-unsubscribe@...</a>
>>
>> </pre>
>> </blockquote>
>> </body>
>> </html>
>>
>> - --------------070905040703020903050202--
>> - -----
>> To get off this list send mail to omc-boats-unsubscribe@...
>>
>> ------------------------------
>>
>> End of omc-boats-digest V1 #581
>> *******************************
>>
>> -----
>> To get off this list send mail to
>> omc-boats-digest-unsubscribe@...
>
> -----
> To get off this list send mail to omc-boats-unsubscribe@...
>

-----
To get off this list send mail to omc-boats-unsubscribe@...
Received on Tuesday, 12 September 2006