350 mag vs 350

[Cptkid570]

What is the difference between a standard mercruiser 260 hp motor (350 chevy) and the 350 mag motor?

 

[Big Boat Bay Buster]

Re: 350 mag vs 350

About 10 Horsepower. This question has been asked before. I don't think you are going to get a straight answer. I have an 1987, 260. I believe this year also had a magnum 350. My 260 has a flat tappet cam, the magnum probably has a roller cam. Mabey some stronger internals? Going to a newer marine vortex smallblock, with a correct performance rollercam, will out-perform the stock magnum anyday.
Chris

 

[180shabah]

Re: 350 mag vs 350

If memory serves the difference wasn't even that extensive, just a high-rise manifold.

 

[twostroke87]

Re: 350 mag vs 350

I was taught in tech school that any engine with *magnum* plastered on the side, indicates a forged steel camshaft and/or crank. instead of the standard cast iron

 

[Bondo]

Re: 350 mag vs 350

I was taught in tech school that any engine with *magnum* plastered on the side, indicates a forged steel camshaft and/or crank. instead of the standard cast iron

Ayuh,....

And you were probably taught Wrong....

Marketing has little or nothing to do with building motors...

There's another thread in the 1st couple of pages on the forum about the Same topic,...
I think Shaba has it Right...

 

[180shabah]

Re: 350 mag vs 350

I was taught in tech school that any engine with *magnum* plastered on the side, indicates a forged steel camshaft and/or crank. instead of the standard cast iron

Then what do "HEMI", "iForce", and "Triton" indicate?????

 

[180shabah]

Re: 350 mag vs 350

I can't believe that I forgot "Vortec"

Like Bondo said - marketing and components are not directly related.

I have a 4.3 "vortec" in the boat and guess what, no vortec heads. And let's not forget the the old "262 Magnum" - there has NEVER been a forged crank in any production 4.3

 

[mkast]

Re: 350 mag vs 350

According to Mercruiser Parts.com, there are two part numbers that are different between 1987 260hp and the 1987 (non roller) Mag.
Intake manifold and carburetor. All the other part numbers are the same block, crank, rods, pistons etc.

 

[twostroke87]

Re: 350 mag vs 350

Ayuh,....

And you were probably taught Wrong....

Marketing has little or nothing to do with building motors...



I actually wasn't taught wrong, I also contacted mercruiser.

Regular 350: Cast iron pistons
Cast iron crank
Regular intake manifold
260 hp

350 Magnum:
Steel pistons
Steel crank
High rise intake manifold
270hp

Nothing to do with marketing, truley magnum engines use steel internal components, not cast iron. The next step up would be billet materials.

 

[Big Boat Bay Buster]

Re: 350 mag vs 350

I don't think you are going to get a straight answer.
Chris

I guess I was right!!

 

[Bondo]

Re: 350 mag vs 350

I actually wasn't taught wrong, I also contacted mercruiser.

Regular 350: Cast iron pistons
Cast iron crank
Regular intake manifold
260 hp

350 Magnum:
Steel pistons
Steel crank
High rise intake manifold
270hp

Nothing to do with marketing, truley magnum engines use steel internal components, not cast iron. The next step up would be billet materials.

Ayuh,.... Really.....
Can't says that I've Ever even seen a Cast Iron, muchless a Steel piston in a SBC....
In Any motor for that matter,.... Ever.....

The next step up would be billet materials.

Ayuh,... I donno whether it's Billet, or Bull$h!t.....

 

[twostroke87]

Re: 350 mag vs 350

my apologies, cast aluminum pistons in the 350 and forged steel in the mag.

billet or bull****? are you kidding me

Cast iron = poured hot into a mold

Forged = formed in a mold under extremely high pressures

Billet = Most commonly found in high performance engines, when something is *billet* it means it was wittled into shape from a solid metal form, not forged or casted. If you can imagine how a baseball bat is made from a peice of wood, its kind of like that. Its the strongest of all designs.

 

[dan t.]

Re: 350 mag vs 350

I saw cast iron pistons in a couple of motors the first was a modle T, the second was a 1951 235 cid chev 6 cyl that I overhauled about 15 years ago for a fellow doing a restore. as for steel pistons? never heard of any in 35 years of pulling wrenches

 

[Tail_Gunner]

Re: 350 mag vs 350

Then what do "HEMI", "iForce", and "Triton" indicate?????

Triton.......90 degree v8...the old 427 cut down to 281 or a 325...totally stud engines........if only ford would get them to breathe ...or at least let the info out to the public.....


OkOk i left out the mains..but you need to have something to talk about....

 

[Bondo]

Re: 350 mag vs 350

my apologies, cast aluminum pistons in the 350 and forged steel in the mag.

Ayuh,.... Your Lack of knowledge is showing.......

And,...
You don't have to explain manufacturing processes to me,...
I already Know,.... You're the 1 who seems to be Missing the point....

According to Mercruiser Parts.com, there are two part numbers that are different between 1987 260hp and the 1987 (non roller) Mag.
Intake manifold and carburetor. All the other part numbers are the same block, crank, rods, pistons etc.

Maybe You should be doing your own Research,...
Rather than relying on Bad info from a marketing expert at Mercruiser....

 

[John_S]

Re: 350 mag vs 350

According to Mercruiser Parts.com, there are two part numbers that are different between 1987 260hp and the 1987 (non roller) Mag.
Intake manifold and carburetor. All the other part numbers are the same block, crank, rods, pistons etc.

I found the same in the research I did. The carb differences was just the tune. It was a richer calibration in the Mag. In some years, the timing module was different, too. In general, it is only a marketing gimick that worked very well. Many people who just touch on boating, think the 350 Mag is a high-performance engine.

 

[180shabah]

Re: 350 mag vs 350

Steel pistons???? so just how much would one of these weigh, and do you have any idea just how much stress would be created at 5000RPM????? You might get a couple of WOT runs before the bottom end exploded into the bilge.

 

[mkast]

Re: 350 mag vs 350

I actually wasn't taught wrong, I also contacted mercruiser.

The last time I talked to the Engineering Department at Mercruiser in Fond du Lac, Wisconsin, I was told:
1. GM builds the engines Mercruiser uses.
2. GM uses the same parts as standard engine, cast pistons etc.
3. GM installs engine accessories on the engine assembly line using
GM (USCG) modified GM parts.

I don't know WHO you talked to at Mercruiser, but some person using terms like steel pistons should keep to washing boats instead of guessing what engine parts are made of.

But, you raise a good question,
Is the steel piston made of stainless steel to curb corrosion?

 

[etkeeny]

Re: 350 mag vs 350

I have a 1987 Magnum 350 in my Sea Ray, the difference that I've found between the regular 350 and the Magnum are as follows,

1. Reg 350 has older style heads with bolts around the perimiter of the valve covers, the magnum has newer style heads with the bolts down the center of the cover.

2. the regular 350 has the old block with the 2 piece rear main seal, the magnum has the newer block with the one piece rear main seal.

3. not sure about the camshafts yet.

Hope this helps

 

[Bondo]

Re: 350 mag vs 350

Ayuh,....

etkeeny,...

The differences stated in #1,+ #2 are merely due to Vintages....

1987 was the 1st year for the valve cover,+ the rear main seal changes... For ALL SBCs...