350 vs 350 magnum

[bones774]

I have a 350 magnum and it is listed as 270 hp, 10 more than a regular 350, the specs for both engines are the same including compression, i'm having a debate with a friend about the difference between engines, some say pistons, others say cranks, 2 bolt or 4 bolt main. anybody know for sure? thanks

 

[Philster]

Re: 350 vs 350 magnum

One of these: More precise fuel delivery (better MPI vs. EFI just one example) and/or better air flow intake and/or slightly less restrictive exhaust.

 

[bones774]

Re: 350 vs 350 magnum

One of these: More precise fuel delivery (better MPI vs. EFI just one example) and/or better air flow intake and/or slightly less restrictive exhaust.

In my case it's a 1988 motor, carbed.

 

[mkast]

Re: 350 vs 350 magnum

Go to:
http://mercruiserparts.com
You can compare parts in different engines (using part numbers).
Then you may find out it's advertising.

 

[msojjo]

Re: 350 vs 350 magnum

I was actually wondering the same thing. From what i just read is it really just the fuel delivery? I have a 2000 350mag pushing out 300, or so it says. I need a new block on mine, and wanted to make sure that there wasn't a difference between internals on a regular 350, and a mag. Anymore help or comments on this matter would answer a few questions

 

[John_S]

Re: 350 vs 350 magnum

In my case it's a 1988 motor, carbed.

Probably just the hi-rise dual plane VS low-profile, on the intake. Carb jetting and maybe a slight timing difference.

 

[John_S]

Re: 350 vs 350 magnum

I was actually wondering the same thing. From what i just read is it really just the fuel delivery? I have a 2000 350mag pushing out 300, or so it says. I need a new block on mine, and wanted to make sure that there wasn't a difference between internals on a regular 350, and a mag. Anymore help or comments on this matter would answer a few questions

It would be helpful to know if you mean: short block, long block, or just the block. and what you mean by a "regular 350" (the 250hp 2brl of same year?). You can find most of what you need in the same link mkast provided.

 

[Philster]

Re: 350 vs 350 magnum

Jeeze, cleaner, more refined intake runners could be worth 10 HP. Doesn't take much, folks.

 

[JES233]

Re: 350 vs 350 magnum

My 92 mag motor has a bowtie intake and a thermo-quad carb.I have never found any cam spec's

 

[mkast]

Re: 350 vs 350 magnum

From Mercruiser #15:
SBC
Lobe Lift +or- .002 intake .263 or .287
exhaust .269 or .300

Duration @.050 intake 269 degrees or 296 degrees
exhaust 283 degrees or 307 degrees

BBC
Lobe Lift +or- .002 intake .300
exhaust .300
Duration @.050 intake 224 degrees
exhaust 224 degrees

 

[Philster]

Re: 350 vs 350 magnum

Did I read that correctly? That compares cam specs on a Big Block vs Small Black, but the open 10-horsepower question is about a 350 versus 350 Mag.

 

[180shabah]

Re: 350 vs 350 magnum

Probably just the hi-rise dual plane VS low-profile, on the intake.

BINGO!

The intakes are different, everything else is the same, well except the stickers and the price.

 

[45Auto]

Re: 350 vs 350 magnum

The intakes are different, everything else is the same, well except the stickers and the price.

Close, but no cigar.

The carbs are also jetted slightly different. Note the specs on the standard 350 outlined in red and the 350 Magnum outlined in blue. Different jets, metering rods, and hangers. From Mercruiser Manual #9, 1985-1988 GM V8's, page 5C-2:

 

[TilliamWe]

Re: 350 vs 350 magnum

Probably just the hi-rise dual plane VS low-profile, on the intake. Carb jetting and maybe a slight timing difference.

That's what is was back in the early 80's. The "famed" Z-28 Hi-Rise intake manifold.

 

[bones774]

Re: 350 vs 350 magnum

That's what is was back in the early 80's. The "famed" Z-28 Hi-Rise intake manifold.

The "famed" Z-28 intake is that good or bad? mines a 88 how can i tell?
Thanks

 

[John_S]

Re: 350 vs 350 magnum

The "famed" Z-28 intake is that good or bad? mines a 88 how can i tell?
Thanks

Remove flame arrester and take a picture from the side. Post, and will let you know.

 

[180shabah]

Re: 350 vs 350 magnum

The carbs are also jetted slightly different.

Sorry, yes the tuning is different, but all of the other hardware, crank, pistons, cam, heads, etc is the same.

 

[Mkos1980]

Re: 350 vs 350 magnum

The hi-rise intake has a bowtie in front of the distributor. These intakes are gold with circle track racers. I find them at swap meets for 40 bucks and resell them for $100+ on eBay. The intake is on par with the Edelbrock RPM intakes. Not the low rise performers.

 

[TilliamWe]

Re: 350 vs 350 magnum

The "famed" Z-28 intake is that good or bad? mines a 88 how can i tell?
Thanks

It's good. The bowtie as mentioned can tell them apart, but also as mentioned take a picture. The hi-rise manifold is physically taller where the carb mounts. Obvious to the eye, at least to many people's eyes.

 

[bones774]

Re: 350 vs 350 magnum

It's good. The bowtie as mentioned can tell them apart, but also as mentioned take a picture. The hi-rise manifold is physically taller where the carb mounts. Obvious to the eye, at least to many people's eyes.

Pic will have to wait, boat is at another location. Thnaks