Author Topic: CV16SS V8 Conversion  (Read 4729 times)

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Offline S2000

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CV16SS V8 Conversion
« on: January 27, 2018, 10:47:47 AM »
Greetings, I am new to this forum and I do have a question.
Just to be clear, I am not intending to do what I'm inquiring about for two reasons: 1) the Mercruiser engine/drive line in my CV is just fine; 2) at my age I don't know if I still have the motivation to attempt such a project.
The question: Is it feasible (even possible) to convert a 140HP Mercruiser set-up to a small block chevy V8? A friend of mine and myself quite often discuss the possibilities, but he's a true car crafter at heart (also a boater) and would look upon such a project as a challenge. I would view it as the possible destruction of a perfectly good classic CV. Just wondering.....

Jim K 

Offline fireman24mn

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Re: CV16SS V8 Conversion
« Reply #1 on: January 27, 2018, 10:56:09 AM »
They made a cv 16 with a v8 from the factory. It was a 302 with a Volvo drive though.
I think this has become an addiction.


1977 CV-23 I/O Full Resto complete
1976 CV-16 V8 Resto in progress
1985 Pearson MotorYacht 43ft

Offline Rich_V174SS

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  • 1967 V174 Crestflite SuperSport Modified
Re: CV16SS V8 Conversion
« Reply #2 on: January 27, 2018, 11:30:11 AM »
Sure it's possible using a donor boat with a full V8 package of engine, drive, and transom assembly. The biggest problem with trying to convert the existing setup is going to be the exhaust system unless you go with thru-hull open exhaust. On a lot of the older transom assemblies they were specific about which internal exhaust pipe could connect to them. The choices were inline 4 & 6 cylinder engine vs. V8. It's often easier to replace everything as a whole. But then there's the problem of the engine cover to conceal it all. Most of the covers were designed to fit the engine that's underneath, to allow room for location of the carburetor and exhaust elbows. A Volvo 4 cylinder engine cover was different than a Mercruiser 4 cylinder cover because the carburetor was on the opposite side. You could also run into a problem using a V8 with new style center-rise exhaust manifolds versus the low-profile manifolds that were in use during the 70's. New style manifolds might not fit under the cover.

IF you even get that far, the drive that's attached needs to be the correct gear ratio to match the horsepower. Using a drive with a 2:1 ratio meant for a 4 cylinder will over-rev a V8 that would normally use a 1.5:1 gear ratio. You can compensate to an extent with a larger prop but the pitch would have to be really high.
« Last Edit: January 27, 2018, 11:34:16 AM by Rich_V174SS »
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115

Offline Hyperacme

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Re: CV16SS V8 Conversion
« Reply #3 on: January 27, 2018, 12:10:58 PM »
Don't think it would be worth converting to the Glastron / Volvo V8 302 / 280 drive.
Jason's CV16SS ( same CV as yours) get with in a few MPH/GPS of top speed of G/V 302 V8.


Offline Hyperacme

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Re: CV16SS V8 Conversion
« Reply #4 on: January 27, 2018, 12:13:34 PM »
Chris found one with a Merc V8, looked factory maybe one off or special order ?   Sorry no pictures ...
http://forum.cgoamn.com/index.php?topic=3374.msg39163#msg39163

Some pictures of a converted CV16 / Merc V8
Is that a Ford 302 V8 ?

Offline Plugcheck

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Re: CV16SS V8 Conversion
« Reply #5 on: January 27, 2018, 01:27:49 PM »
It certainly can be done, but I would not recommend doing so unless the the boat is a basket case, and you have a donor craft available.  A much easier and better way would be to find a larger Glastron with a V8 setup.
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude

Offline S2000

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Re: CV16SS V8 Conversion
« Reply #6 on: January 27, 2018, 04:28:28 PM »
Yeah, at only 50mph it doesn't make much sense. With my stainless 21" cleaver and a slippery hull I can do better than 45mph. Other than the cool sound of a V8 with Captains Call exhaust, to me there would be no benefit. If I want cool sound, as well as 47mph, my Malibu Response fills that need. The originality and economy of Merc 4 cyl is more important.

Offline Hotwired

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Re: CV16SS V8 Conversion
« Reply #7 on: January 27, 2018, 10:33:23 PM »
Hey Stangers ..... If anyone is interested, I have a CV16ssV8 hull on a trailer that if anyone wants to come to Phoenix to get it ...... this last pic is the hull up for grabs.

and yes, I do have the only factory V8 Mercruiser boat I have eve seen. 50 is tops.  with the 302.  With More HP it will do a lot more.  I know one converted CV-16 that I saw up at Ottertail that with the help of a healthy 350 and a modifed drive (Adams boat I think) ran like a scalded dog!



« Last Edit: January 27, 2018, 11:15:19 PM by Hotwired »
.. it is what it is ... and that is how it should be!
Miss Mayberry - 1964 Saberflite
The Ship - 1979 CV-27
Canon Ball Eyes - 1976 CV-16ssV8
Da ProJect Bote - 1977 CV-23
It Is What It Is...... CVX20

Offline Hyperacme

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Re: CV16SS V8 Conversion
« Reply #8 on: January 28, 2018, 09:03:18 AM »
Oh Ya ...
Adam's CV16SS with a 350 ci and Mercruiser.
Think it was good for about 70 mph.

Offline Hotwired

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Re: CV16SS V8 Conversion
« Reply #9 on: January 28, 2018, 10:03:17 AM »
that's him ....
.. it is what it is ... and that is how it should be!
Miss Mayberry - 1964 Saberflite
The Ship - 1979 CV-27
Canon Ball Eyes - 1976 CV-16ssV8
Da ProJect Bote - 1977 CV-23
It Is What It Is...... CVX20

Offline 75starflight

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Re: CV16SS V8 Conversion
« Reply #10 on: January 28, 2018, 02:53:23 PM »
He doesn't have that one anymore I believe.
1975 v-179 starflite

Offline Plugcheck

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Re: CV16SS V8 Conversion
« Reply #11 on: January 28, 2018, 03:47:57 PM »
  I remember discussing the project with him at Kini park, had an odd displacement like 331, bored 327 or something like that.  It did run hard, but conditions on the river were not good that day for small boats.    I seem to recall the boat was in rough shape, so he rebuilt it like this.  Like Brandon said, he no longer has the boat due to personal reasons.
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude