Best aftermarket carb for 81 260 (5.7)

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I'm in need of a new carburetor, the old carb I took off the boat had been rebuilt by a 6 year old (or so it seems) I've got rods bent, missing, the base plate has a huge scratch in it that will never seal and there wasn't a single check ball thought the entire carb. So my question is what is the best aftermarket carb to get for my 1981 Mercruiser 260 engine? It's completely stock but I do plan on getting an intake manifold next year but want to see this boat run in the water at least two times without problems. Oh and I have a carb spacer so the stock intake manifold can accept a 4bbl carb. The boat is a 21 ft Tahiti... Thanks
 
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Re: Best aftermarket carb for 81 260 (5.7)

Thanks! The carb they list is a Mallory for around $650! I was hoping to use an Edelbrock since that's what I run in my truck. What CFM is going to be best for my application? The search feature isn't very useful... I did try :facepalm:
 

achris

More fish than mountain goat
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Re: Best aftermarket carb for 81 260 (5.7)

ok... The Edelbrock 1409 is perfect for your application... Many many people here have changed over and are happy with it....

As for CFM... A 350 running at 5000rpm at 85% volumetric efficiency needs no more than 430CFM... The 1409 is 650cfm...

Chris......
http://www.summitracing.com/parts/edl-1409
 
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Re: Best aftermarket carb for 81 260 (5.7)

Thanks again man, I put a 750 CFM on there just to hear it start and run but since its a car carb I haven't taken in out on the water yet.
 
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Re: Best aftermarket carb for 81 260 (5.7)

After checking summit it list this carb as a 600 CFM carb... Is that going to be big enough for when I upgrade the intake to an aftermarket one? Also, is a car intake and marine intake the same? What about cylinder heads? I know battery's, carbs, distributors and engine blocks are different than automotive parts. Sorry for the ignorant questions... I'm new to boating. I do plan on port matching the heads to whatever intake I choose.
 

achris

More fish than mountain goat
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Re: Best aftermarket carb for 81 260 (5.7)

Rather not hear about car carbs on boat engines.... :boom:
 

achris

More fish than mountain goat
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Re: Best aftermarket carb for 81 260 (5.7)

After checking summit it list this carb as a 600 CFM carb... Is that going to be big enough for when I upgrade the intake to an aftermarket one? Also, is a car intake and marine intake the same? What about cylinder heads? I know battery's, carbs, distributors and engine blocks are different than automotive parts. Sorry for the ignorant questions... I'm new to boating. I do plan on port matching the heads to whatever intake I choose.

Even with a blower, that carb would be more than enough.... When you're doing up your engine, just remember one thing... Marine engines are all about having a flat torque curve, not a peaky one.... It might be nice to have an engine that produce 12 million horsepower at 117 thousand revs, but as a boat engine, it's pretty much useless....

I believe a dual plane manifold is the best for producing torque low down, so that it what I would recommend... Don't know where you're running (salt water of fresh) but if you're in salt, stay away from ali...

Chris....
 
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Re: Best aftermarket carb for 81 260 (5.7)

I'm in Oregon running in fresh water only. So a boat and car intake are interchangeable?
 

achris

More fish than mountain goat
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Re: Best aftermarket carb for 81 260 (5.7)

I'm in Oregon running in fresh water only. So a boat and car intake are interchangeable?

Should be... It a 350 GM engine... Standard, 'out of the box' SBC....

Hang on... Oregon?, you got a Pacific Ocean on your doorstep!!! Sorry to inform, that's SALT my friend... :D (Almost moved there a few years back... ;))

And why you up so late?

Cheers.
 

geneseo1911

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Re: Best aftermarket carb for 81 260 (5.7)

I have read that even in fresh water, especially fresh water that has a high mineral content, electrolysis will still eat aluminum, albeit much slower. That said, I still intend to put an Edelbrock Performer on my boat...one of these days. Maybe when I do a TBI. Might do aluminum heads some day, too, and aluminum exhaust is on the short list. Weight savings will do more for boat performance than more horsepower. The Mercruiser 260 is essentially a Chevy truck 350, with marine specific carb, distributor, alternator, starter, & cam, so any small block bolt ons, will fit, but please be careful to make sure the ones listed above are marine versions if you replace any of them.

The Edelbrock 1409 is said to be nearly perfect out of the box for v-8 applications. I have one (came on the boat), and it runs well, my only gripe is with the idle, but I have yet to see a carb that always produces a perfect idle.
 
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Re: Best aftermarket carb for 81 260 (5.7)

Should be... It a 350 GM engine... Standard, 'out of the box' SBC....

Hang on... Oregon?, you got a Pacific Ocean on your doorstep!!! Sorry to inform, that's SALT my friend... :D (Almost moved there a few years back... ;))

And why you up so late?

Cheers.

I realize Orergon has access to salt water, but hat doesn't mean I take my boat in the ocean. I'm plaining on taking it to lakes? around 150 miles away from ocean.

I never fall asleep before 2-3am pst
 
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Re: Best aftermarket carb for 81 260 (5.7)

The Mercruiser 260 is essentially a Chevy truck 350, with marine specific carb, distributor, alternator, starter, & cam, so any small block bolt ons, will fit, but please be careful to make sure the ones listed above are marine versions if you replace any of them.

The Edelbrock 1409 is said to be nearly perfect out of the box for v-8 applications. I have one (came on the boat), and it runs well, my only gripe is with the idle, but I have yet to see a carb that always produces a perfect idle.

That's exactly the kind of information I was looking for, thank you. Why can't I upgrade the cam? Is it because of the torque curve?
 

Volphin

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Re: Best aftermarket carb for 81 260 (5.7)

You can upgrade the cam. Put a Comp Cams XM270 on your list. If you want lighter manifolds, go with Hi-Tek. I love mine.
 

geneseo1911

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Re: Best aftermarket carb for 81 260 (5.7)

Yes, there are other cams you can use; the issue is that if the cam has too much overlap, the engine can suck water back into the cylinders, known as reversion. I'm not an expert, but there is lots of threads around here on what constitutes the best cam. You do want a broad, flat torque curve that comes on at low RPM.
 

mike165

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Re: Best aftermarket carb for 81 260 (5.7)

I run a 600cfm Vac back 4b Holley on a 350 Vortec Mercruiser crate motor 330HP 14x23 4b 1.1.5 ratio 215 Bayliner 5k @ 80kph avg fuel 22l-hour around 3800rpm best combination I've had
 
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