Engine dudes...Help Me build a 350!


Almost A Member
Jun 3, 2004
'nard and ventura
Boat Name
radon 27
On a budget and building 2 of them.
I'm replacing 2 454s. I know 2 guys with the same hull that changed over to 350s and get way better gas mileage. Seems the MPI ones get way better at idle but are really close to the carbed at cruise.
Boat is a Radon 27 with Douprops, will reuse drives.

Ok, What do you think of these for $1549:

GM Goodwrench 1970-85 350 Engine & Packages

GM Performance
GM Goodwrench 1970-85 350 Engine & Packages

Product images may differ from actual product appearance.

This universal 350ci engine uses a brand new block and can be used as a replacement for most GM vehicles from 1970-85. It produces 260 HP and 350 ft/lbs of torque with a 4-bbl carb and headers. It can be used as a replacement or as a retrofit into almost any vehicle. This brand new crate engine comes with a GM warranty and is covered for 3 years or 100,000 miles in applicable GM vehicles only.

# 4-bolt main with 2-piece rear main seal
# Cast iron crankshaft
# LT1/LT4 powdered metal connecting rods
# Cast pistons (dished)
# Hydraulic flat tappet cam (.383''/.401'' and 112° lobe separation)
# Cast iron cylinder heads with 76cc chambers
# 8.5:1 compression ratio
# Left and right hand dipstick
# 4-quart oil pan
# Timing tabs for a 6-3/4'' or an 8'' balancer
# Recommended spark plug: Accel #111-574 or any spark plug with 14mm .460'' reach, 5/8'' hex, tapered seat, projected tip
# GM recommends the use of a melonized distributor gear (#270-11951-1)

Ok , now lets build the rest.

Upgrade head gaskets and freeze plugs.
Bigger oil pan necessary?

What Camshaft would you go with?
What intake manifold?
I love Edelbrock carbs, that is what I'll be using.

Will use the Mercruiser Dry Joint exhaust system.
Engines will be RAW water cooled.

How about this ignition set?

MichiganMotorz.com 5.7L GM Delco Voyager EST marine electronic distributor kit

Marine starter, Alt, fuel pump.

What do you experts think so far?

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May 29, 2008
Cambutal, Panama
Boat Name
Mako CC
You can get marinized 383s for the same money, more torque and it's a great fit for the Edelbrock marine carb. They come with everything but the sheet metal, including the intake manifold. You won't have to dick with head gaskets, freeze plugs or any of that stuff since they are built that way.

In a boat, I wouldn't use anything but the Mallory billet distributor especially if you are going to run it hard.

You're missing a few bits and pieces, but having done several of these, figure 4k each if you do "all" your own labor. In your case where you can't reuse flex plates and such, probably several hundred more.

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Aug 4, 2003
Mission Viejo, CA
Visit site
Boat Name
28' Skipjack Flybridge
Been there, done that!

I spent a lot of time pricing out a couple of carbed 350s for my Skippy and you can't beat the price of a drop-in unit from Marine Power. You can get a closed cooled unit for around 6K.

You'll see for yourself, once you price out the parts (never mind the labor to build it), you'll be breaking even ... then you'll have the bellhousings, flexplates, etc., to finish the job.

Do yourself a favor and buy a complete engine, if you don't have the parts to swap over from your old one ... and even then, you may be asking for problems down the road with the wear and tear on the older parts. At least with a drop in unit from Marine Power you'll have a nice two year warranty ... just my two cents!
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Liquid Therapy
Aug 29, 2005
san diego
Boat Name
Blackman fish machine 26 "First Light"
but a volvo/mercruiser 350 long block, don't try to marinize a car engine your self, not worth it. I got my long block for my skippy from s&s engines, and two years from when I bought it a head cracked, they replaced it no questions asked.
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"It's all Good!"
May 9, 2006
Gilbert, AZ
Boat Name
26' Sea Ray, "yes dear..."
There's alot more to it than what the specs state. They, (marine engines), usually have steel cranks and better pistons. For a cam, use only a marine cam or a marine cam copy from Crane, GM, Cam Dynamics, Lunati etc.

Raw water and aluminum manifolds don't mix unless it's the spendy one with the bronze inserts.

Use a truck or marine oil pan, at least 6-8 quarts.

About all for now.

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I Post A Lot But I Can't Edit This
Nov 5, 2003
So Cal
You couldn't say it anyway
Boat Name
24' Skipjack open "UnReel"
I'd PM Tuner . He built my 350 votec for my skip and it's sweet !!!
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