Mercruiser 5.7L HP Rating ??

[hwy39]

I just purchased a 1996 Sea Ray w/5.7L Mercruiser 350CI. The horse power rating is 210HP. I thought the 5.7L basic was a 260 HP rating. What is the difference?

 

[Wart T]

Re: Mercruiser 5.7L HP Rating ??

I'd like to know also. My manuals show ratings of 235, 250 and 265. Sometimes I think they just pull those HP numbers out of their rear ends.

 

[John_S]

Re: Mercruiser 5.7L HP Rating ??

The '97 5.7L (2brl)/Alpha is 210hp in my op manual, '97 brochure, and Merc service manuals. Seloc doesn't have hp rating. Last I checked, the current production 5.7L (2brl)/alpha was 250 hp. http://www.mercurymarine.com/5.7l_sd_-_250_hp I also have been wondering about the differences, but suspect the current model has different heads or pistons (higher compression ratio), cam, and timing profile. It has a higher WOT spec, as well.

 

[Wart T]

Re: Mercruiser 5.7L HP Rating ??

Good info John. My information was from the Seloc, it doesnt list a specific HP for that year.

 

[viperry Scarab]

Re: Mercruiser 5.7L HP Rating ??

Thats odd i was almost positive the current 5.7's where gettin 260 at least thats what crownline with a bravo3 was advertised for. hmm

 

[skicat]

Re: Mercruiser 5.7L HP Rating ??

The HP is measured at the prop shaft. Therefore different drives give different HP's. <br /> <br />Alpha 1 250<br />volvo-penta 260<br />Bravo 3 260<br /><br />This is what I was told. Personally I think volvo fudged some numbers to boost HP and then Mercruiser did the same for their Bravo Drive to stay competitive.

 

[cuzner]

Re: Mercruiser 5.7L HP Rating ??

H.P. should be measured at the prop, but not always done that way.Could be some builders are giving out the engine hp, not useable hp....<br /><br /> just a thought<br /><br /> Jim

 

[jimmbo]

Re: Mercruiser 5.7L HP Rating ??

The pre Vortec 5.7 with 2 barrel carb were around 210 - 220 hp and 250 - 260 with 4 barrel. The Vortec 5.7 put out 250 - 260hp with a 2 barrel. Those Vortec heads flow real nice and allow higher compression without detonation. As for Volvo fudging the numbers. I have a Volvo 5.7 and there are some differences on the carbed engines. Mercrusier uses what looks like a standard 2 barrel intake manifold, Volve uses an intake that looks like the 1968-71 Z28 - LT-1 manifold. and a Holley 500 cfm carb.

 

[hwy39]

Re: Mercruiser 5.7L HP Rating ??

Thanks for all the input. I agree the difference is measuring the HP at crank vs prop which results in a difference of 260HP vs 210HP. If the 4-barrel carb puts out 250 HP at the prop vs the 210 I am currently getting, what all is involved in converting to a 4-barrel and is it worth it?<br /><br />Thanks,<br />hwy39

 

[John_S]

Re: Mercruiser 5.7L HP Rating ??

hwy39,<br /><br />This thread will interest you: http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=007547

 

[fast94impala]

Re: Mercruiser 5.7L HP Rating ??

"what all is involved in converting to a 4-barrel and is it worth it?"<br /><br />hwy39,<br /><br />Just completed the conversion on my 96 5.7l Maxum SRL 2000. Well worth it!! Got another 5 mph and better launching for skiing. Hit 55 yesterday with full fuel and 3 people on board. 2 bbl was good for about 50. Plan on $600 in parts, $20 in beer and a couple evenings or a very full day of wrenching. All depends on how many brackets need to be modified. Unfortunately for me, it was most of them. Nothing a hacksaw and file couldn't fix. Really pretty easy to do.<br /><br />I went with Edelbrock 600 cfm marine(#1409) and dual plane manifold(#2104) for $295 and $159 respectively. Also purchased required square bore spacer and fel-pro intake gaskets and K&N low profile flame arrestor from Summitracing.com. The 4 bbl throttle bracket was obtained from mercruiserparts.com as well as new thermostat, sleeve and gaskets. You'll also need silicone gasket sealer, anti-seize, and teflon thread sealer. Happy boating!<br /><br />Mark

 

[MFG197]

Re: Mercruiser 5.7L HP Rating ??

What model Sea Ray? I have a 96 215 Express 350 Merc A1G2 250hp.<br /><br />I think I have a Weber 4bbl. which I plan on getting rebuilt. I think the accelerator pump is bad. Bogs down sometimes out of the hole. Still hits 50mph though.<br /><br />My original 1996 Sea Ray book says the boat was available with<br />4.3 V-6<br />5.7 v8 210 hp<br />and <br />5.7 V8 250 hp

 

[hwy39]

Re: Mercruiser 5.7L HP Rating ??

WWYC na7<br />Sorry for the long delay in reply. Boat is a 96 Signature 21' bow rider. 5.7v8 210hp. After reading all the info i don't beleive I will see any significant improvement going to a 4bbl. If mine was a vortec then I would

 

[dygrp]

Re: Mercruiser 5.7L HP Rating ??

Whats the difreance between 5.7 and 260 on a 350 ci engine. My engine only says 260 and the boat i used to have had a 5.7( both mercs)

 

[skicat]

Re: Mercruiser 5.7L HP Rating ??

5.7 is 350 cubic inches converted to liters<br />260 is the horsepower

 

[tylerin]

Re: Mercruiser 5.7L HP Rating ??

94 SeaRay 5.7 w/ a Merc/Weber/CarterAFB Carb (whatever you want to call it) 260 hp. WWYC use the Carter street/strip rebuild kit for your carb, much cheaper

 

[dygrp]

Re: Mercruiser 5.7L HP Rating ??

i thought so thanks for clearing it up, skicat

 

[dygrp]

Re: Mercruiser 5.7L HP Rating ??

another question, i just got this boat and the cooling hoses do not go into the exhaust manifold and exhaust elbow? i'll try to post a picture, previous owner has it returning to thermostat housing?

 

[dygrp]

Re: Mercruiser 5.7L HP Rating ??

 

[dygrp]

Re: Mercruiser 5.7L HP Rating ??

that didnt work maybe this:<br /> http://f1.pg.photos.yahoo.com/ph/dygrp/album?.dir=/e478