Reply
 
Thread Tools Search this Thread Display Modes
 
Old 10-08-2017, 11:45 AM   #1
Commander
 
Join Date: Jul 2011
Posts: 345
Default New 357s in my 3200 SCR

I replaced my old-style merc 5.7L 260HP engines with a pair of Mercruiser 357 Magnum Bravo 4V, they are rated at 325HP each.

My boat: 1995 3200 SCR, with Bravo IIs.
Half tank gas, water tank empty, holding tank quarter full.
Just me an my mechanic on the test run.
Nearly flat water, wind less than 2 knots.

Planes quicker, I didn't time it but will get some timings soon.
Pushed throttles wide open, engines are rated 4400-4800 rpm, mine got right to 4800. Didn't really trim it that much, was doing 37 mph.

Very happy with them so if anyone is ever considering what options these are pretty decent for the price.

Some links on line:

https://www.mercurymarine.com/en/us/...specifications
__________________

jamanati is offline   Reply With Quote
Old 10-08-2017, 11:48 AM   #2
Commander
 
Join Date: Jul 2011
Posts: 345
Default

In my boat, took these at night though, so they aren't that clear.
But....

Click image for larger version

Name:	20171003_190910.jpg
Views:	17
Size:	265.4 KB
ID:	5229

Click image for larger version

Name:	20171003_190902.jpg
Views:	12
Size:	645.1 KB
ID:	5230
__________________

jamanati is offline   Reply With Quote
Old 10-08-2017, 12:19 PM   #3
Admiral
 
mmwjr's Avatar
 
Join Date: Feb 2012
Location: Essex, Maryland
Posts: 10,176
Default

Very nice. According to the video the engine has a mechanical fuel pump so it a pre-Vortec rebuild. Last year I dropped in a new 5.7 Vortec but used the old bolt on stuff and rebuilt the Weber carb. She is rated at 320 HP. Definitely can feel the power increase over the old 260 HP.

Enjoy
__________________
1997 Silverton 362, 7.4 Crusaders
1997 2400 SCR, 5.7 Vortec / Bravo 2

Mike
mmwjr is offline   Reply With Quote
Old 10-10-2017, 02:29 AM   #4
Commander
 
Join Date: Jul 2011
Posts: 345
Default

Even though it does have a mechanical fuel pump, it is indeed a Vortec engine, has 8-bolt intake, heads. Mercruiser drills the block to accept the mechanical fuel pump. It would be a challenge to get 325hp from a 4-bbl carb, 356 cu in without the engine being a vortec design.
jamanati is offline   Reply With Quote
Old 10-10-2017, 11:41 AM   #5
Admiral
 
mmwjr's Avatar
 
Join Date: Feb 2012
Location: Essex, Maryland
Posts: 10,176
Default

Quote:
Originally Posted by jamanati View Post
Even though it does have a mechanical fuel pump, it is indeed a Vortec engine, has 8-bolt intake, heads. Mercruiser drills the block to accept the mechanical fuel pump. It would be a challenge to get 325hp from a 4-bbl carb, 356 cu in without the engine being a vortec design.
Strongly disagree that it would be a challenge to build a high HP non-Vortec 350. This was done all the time in the 70's and 80's and engine builders are still doing it.
__________________
1997 Silverton 362, 7.4 Crusaders
1997 2400 SCR, 5.7 Vortec / Bravo 2

Mike
mmwjr is offline   Reply With Quote
Old 10-11-2017, 02:15 PM   #6
Captain
 
Kevlar7r's Avatar
 
Join Date: Aug 2014
Location: Jacksonville, FL
Posts: 746
Default

Quote:
Originally Posted by mmwjr View Post
Strongly disagree that it would be a challenge to build a high HP non-Vortec 350. This was done all the time in the 70's and 80's and engine builders are still doing it.
Our 1967 Firebird 400ci is doing over 500hp on a 650 cfm Holley and pump gas.

Nascar 350's do 900hp on a 4 barrel carb (fuel injected now) with a restrictor plate.



Sent from my SM-G930P using Tapatalk
Kevlar7r is offline   Reply With Quote
Old 10-11-2017, 04:09 PM   #7
Admiral
 
mmwjr's Avatar
 
Join Date: Feb 2012
Location: Essex, Maryland
Posts: 10,176
Default

Not sure I would use a NASCAR engine for comparison as its a much different animal. But the L-48 version put out 295HP and the LT-1 that was used in the 1970 corvette put out 370HP but that had 11:1 compression. The Vortec heads help creating high HP using low octane.
__________________
1997 Silverton 362, 7.4 Crusaders
1997 2400 SCR, 5.7 Vortec / Bravo 2

Mike
mmwjr is offline   Reply With Quote
Old 10-11-2017, 04:17 PM   #8
Captain
 
Kevlar7r's Avatar
 
Join Date: Aug 2014
Location: Jacksonville, FL
Posts: 746
Default

Quote:
Originally Posted by mmwjr View Post
Not sure I would use a NASCAR engine for comparison as its a much different animal. But the L-48 version put out 295HP and the LT-1 that was used in the 1970 corvette put out 370HP but that had 11:1 compression. The Vortec heads help creating high HP using low octane.
Yea, my first comment was really the comparison. Just was thinking about how much you really can squeeze out of the same displacement

Sent from my SM-G930P using Tapatalk
Kevlar7r is offline   Reply With Quote
Old 10-11-2017, 11:19 PM   #9
Commander
 
Join Date: Jul 2011
Posts: 345
Default

True, can build out a custom marine engine out of 350 cu in to crank out more than 300 HP. Would need ported/specific heads, custom valves, aggressive cam, roller/lifter set, timing tuning, carb tuning, etc. Not saying it isn't possible, but it's a challenge to do it with standard, easily available marine parts from your local marine shop. Plus it gives 3 year warranty. I'm happy with them is just my point.
jamanati is offline   Reply With Quote
Old 10-12-2017, 01:15 AM   #10
Admiral
 
mmwjr's Avatar
 
Join Date: Feb 2012
Location: Essex, Maryland
Posts: 10,176
Default

Quote:
Originally Posted by jamanati View Post
True, can build out a custom marine engine out of 350 cu in to crank out more than 300 HP. Would need ported/specific heads, custom valves, aggressive cam, roller/lifter set, timing tuning, carb tuning, etc. Not saying it isn't possible, but it's a challenge to do it with standard, easily available marine parts from your local marine shop. Plus it gives 3 year warranty. I'm happy with them is just my point.

I hear you and I would be very happy with the engines you picked, I was just saying a pre Vortec engine is capable of high HP from the factory back in the day and it was done without being that aggressive of a build. Today's engines can do it by advancing the timing much further since they incorporate a knock sensor to protect them.
__________________

__________________
1997 Silverton 362, 7.4 Crusaders
1997 2400 SCR, 5.7 Vortec / Bravo 2

Mike
mmwjr is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Powered by vBadvanced CMPS v3.2.3

All times are GMT. The time now is 08:33 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.