Merc 350 upgrade combo's

[Shabah180]

im curious if anyone has "blown up" a carburated merc 350 mag. Ive heard the bottom end can handle 5200-5400 rpm if paired with the right heads, rollers etc
1) i know down south guys blow up their motors intheir baja's a lot, im in canada and no matter which way you slice it, a repower will run you over 10.000.
2) if anyone has done this project are you able to share your what you did with what products?
Along with a rough cost?

I realize people will tell me " just find a boat with the power you want" but i might be getting a deal ona good 350 for a project motor, so i can leave mine in the boat.

Any info from fellas who know their motors will be great!
Thanks
Cory

'98 Mariah shabah 180
350 mag, bravo III

 

[Scott Danforth]

Anyone who pays $10k for a small block is not that smart. A 540 cubic inch big block is under 7.

For your SBC. Spend $900 on a forged rotating assembly, $500 for a new set of vortec heads, $300 for gskets, core plugs and , $220 for a vortec intake, $900 for EMI exhaust and spend $500 with your local machine shop to put together your 5500 RPM 383 400hp motor

 

[NHGuy]

All of what he says. But the exhaust is more like $1700.
If you get a cam that's not wild you can use normal exhaust. Comp has them grouped in marine, then roller vs. flat tappet, and has the roller cams separated by retrofit style vs oe style. If you get the roller it's easy enough to use the oe style and avoid a bunch of fitting to get a thrust button to keep the cam in place. That's what I did on my 383.
I recommend researching your head for valves that handle whatever lift your cam will generate. You'll need to know that and work it out with whatever chamber volume your pistons have to yield a correct compression ratio. I bought dressed Dart heads and ended up changing the valve springs for beehive springs that could handle the lift and required pressure that the cam called for.
The big cam and big exhaust combination allows you to go for max power, but requires loud exhaust to avoid reversion. If you like big sound and want to go fast do that. Mine turned out good, but even though I have the baffled platform it's so loud I have to get some riser baffles to calm it some more.

 

[scoflaw]

And the forged rotating assembly is more like $1700. Jeg's / Summit. Eagle or Scat which both originate in China.

 

[Shabah180]

Anyone who pays $10k for a small block is not that smart. A 540 cubic inch big block is under 7.
For your SBC. Spend $900 on a forged rotating assembly, $500 for a new set of vortec heads, $300 for gskets, core plugs and , $220 for a vortec intake, $900 for EMI exhaust and spend $500 with your local machine shop to put together your 5500 RPM 383 400hp motor

Thanks, yes in the states things are much cheaper, for me to ship up a new 383 stroker is well over 10 in canada. Keeping your eyes open for boat wtite offs is an option too,

Thanks for the list!

 

[Shabah180]

All of what he says. But the exhaust is more like $1700.
If you get a cam that's not wild you can use normal exhaust. Comp has them grouped in marine, then roller vs. flat tappet, and has the roller cams separated by retrofit style vs oe style. If you get the roller it's easy enough to use the oe style and avoid a bunch of fitting to get a thrust button to keep the cam in place. That's what I did on my 383.
I recommend researching your head for valves that handle whatever lift your cam will generate. You'll need to know that and work it out with whatever chamber volume your pistons have to yield a correct compression ratio. I bought dressed Dart heads and ended up changing the valve springs for beehive springs that could handle the lift and required pressure that the cam called for.
The big cam and big exhaust combination allows you to go for max power, but requires loud exhaust to avoid reversion. If you like big sound and want to go fast do that. Mine turned out good, but even though I have the baffled platform it's so loud I have to get some riser baffles to calm it some more.

Right on buddy! Thanks! Do you know of where to get the parts? Maybe a shop that does this kind of work who can source what id need?
Im not too sure if the local mercruiset mechanic can do rhis type of work? Im just not sure how extensive their training is,
Man, you guys know your stuff with marine engines!

 

[Scott Danforth]

Summit racing sells to canada, and there are machine shops in canada. Ebay has complete RMI manifolds and elbows for $1160 for sbc's. With standard risers. If you watch, you cans find fan'soff sir about $500. Heck, I have a set of BBC lightning headers I'm selling for $1200. Deals are out there

 

[Bondo]

Ive heard the bottom end can handle 5200-5400 rpm

Ayuh,.... Regardless the hard parts ya buy, a full-on Balance job will be some of the best money ya spend on it,.....

 

[Shabah180]

Summit racing sells to canada, and there are machine shops in canada. Ebay has complete RMI manifolds and elbows for $1160 for sbc's. With standard risers. If you watch, you cans find fan'soff sir about $500. Heck, I have a set of BBC lightning headers I'm selling for $1200. Deals are out there

Thanks scott!!
Thats just the thing, i dont know where to watch! Haha!

 

[Shabah180]

Ayuh,.... Regardless the hard parts ya buy, a full-on Balance job will be some of the best money ya spend on it,.....

What does a balance job envolve bondo?

 

[Scott Danforth]

What does a balance job envolve bondo?

A competant machine shop

 

[Scott Danforth]

And the forged rotating assembly is more like $1700. Jeg's / Summit. Eagle or Scat which both originate in China.

I'm paying $1721 for a big block forged scat assembly. Its $2200 at summit. The SBC forged kit is just a tick over $900

Just gotta know where to look. Block bore and gone is $170. Balance work is another $170

 

[G_Hipster]

Internal/external balance crank? My machinist asks for the flywheel. If piecing it out make sure you get compatible parts. Around here a proper balance job is 2 c-notes and worth every penny. The box crank kits balance job is not always spot on and my experience with the aftermarket cranks is that the journals are a touch on the small side. Some machinists will want to do a line bore to tighten up the clearances which can introduce other issues as the bell housing to crank centerline changes.

 

[NHGuy]

Skip white on ebay has awesome deals on this stuff. I think you are able to buy it, aren't you?

 

[NHGuy]

Whatever you do, please keep me looped in. I love this stuff and would be really interested in advising as you work on it.

 

[NHGuy]

Skip white has already balanced assemblies BTW.

 

[Shabah180]

I'm paying $1721 for a big block forged scat assembly. Its $2200 at summit. The SBC forged kit is just a tick over $900

Just gotta know where to look. Block bore and gone is $170. Balance work is another $170

Where did u get all this knowledge??? You and nhguy are right in tune with this stuff, im going to call summit and see what they can put together, from my seriel number, and head castings, ive heard the heads and the correct pushrod length is super important to make bigger horsepower..
theres a lot to it i dont know about but it interests me and i gotta start somewhere.

 

[Shabah180]

Skip white has already balanced assemblies BTW.

Thanks nhguy!! Wish i had a guy like you in the neighbourhood here! Haha! Im going to call summit and get the ball rolling on this over the winter, it looks pretty promising turning the 350 into a 383 it cheaper to build on what i have rather than purchasing a new 383 stroker thats for sure.
She wont even touch the water under full throttle... lol

 

[Shabah180]

Internal/external balance crank? My machinist asks for the flywheel. If piecing it out make sure you get compatible parts. Around here a proper balance job is 2 c-notes and worth every penny. The box crank kits balance job is not always spot on and my experience with the aftermarket cranks is that the journals are a touch on the small side. Some machinists will want to do a line bore to tighten up the clearances which can introduce other issues as the bell housing to crank centerline changes.

Good info thanks buddy!

 

[Shabah180]

Can i just ship my boat to you guys?? Haha!
Just emailed skip white to see if they can put something together.