best budget build for a boat?

1

1935garwoodspeedster

Member
Grumpy,

What would be better for a budget minded marine build a 350 or a 383?
are vortec heads better for 350 build or the 383?
looking to make 350hp in my target range of 3500-4000 if thats even possible...otherwise i would like to make as much power as possible under 4000 RPM, as i would like the engine to live between 3400-4000 RPM with an occasional 5000 RPM flogging.

boat weight should be around 2000 lbs (dry) reproduction 1935 Garwood Speedster.
 
a 383 built with vortec heads, could rather easily make even better power than your requesting , provided you carefully match components

Id start with a decent 10:1 compression 383 short block ,add a set of these heads
http://www.summitracing.com/parts/pmx-2151
and a cam like this
http://www.crower.com/camshafts/chevy-2 ... r-cam.html
intake like this
http://www.summitracing.com/parts/edl-7516
and 1.6:1 roller rockers
keep in mind if this is run in salt water electrolysis will very quickly destroy an aluminum intake unless the water passage areas coated with a non-conductive coating

http://www.tristarengines.com/catalog/h ... heads.html

http://airflowresearch.com/articles/article085/A-P1.htm

taved said:
Folks,

I thought that this would be of interest to some.

I have a mild 383 sbc with GMPP Bowtie Vortech 185cc heads (25534421) and a GMPP Hotcam in a 1972 Chevelle (TH350).

Static compression is calculated at 9.6:1. Cranking compression is 185 psi.

The dyno plots in blue- old exhaust system and stock convertor
stock iron exhaust manifolds, 2.5" true-dual pipes, Summit Turbo mufflers, tips to bumper

The dyno plots in red- new exhaust system and 2400 stall converter
Hooker sbc headers, 2.5" Pypes X-over pipe, 2.5: pipes, Pypes Race Pro MVR30 18" case mufflers, tips to bumper

I wish that I could take the converter off the comparison but it's too late.

Dave

video:


DavidTMalibu_zps347ebde7.jpg
Click to expand...

IF YOU LOOK CLOSELY THE VORTEC HEADS AND HOT CAM ON THAT 383 < OBVIOUSLY PEAKED IN THE 4000rpm-4500rpm RANGE, AS THE TORQUE CURVE DROPS NOTICABLY AFTER THAT RPM, WHICH WOULD BE EXPECTED WITH THOSE HEADS RESTRICTING A 383 , MUCH OVER 4500RPM

380 cu in vortec head build
heres a mild high torque build using a set of mildly reworked vortec heads and a chevy hot cam.
Recently I built a 380 inch small block with 906 Vortec heads for Pat Mcneil. The build: 4.020 X 3.750, 10.1 compression, hyd roller on a steel billet 218/228/112/109/.525, Crane/GM LT 4 1.6 roller rocker arms, very mild, Ferrea 1.940/1.50 stainless valves, GM titanium retainers, GM locators, GM valve springs, the 906 Vortec heads featured honed bronze valve guides, race valve job, spring pockets cut, machined for screw in studs, fully ported, 65 CCs, Performer RPM intake, 850 Holley, 31 degrees total timing, 5 quarts 10/30 Valvoline oil.
IMG_3008.jpg
Click to expand...
2972vt.jpg

IMG_3007.jpg
Click to expand...

If your going to run vortec heads, you either check you have clearance on current heads, with accurate precision tools and/or if you find you don,t have the required clearance,your going to be forced to modify current heads or you could buy heads with the correct clearance


reading the related info will be helpful
http://www.summitracing.com/parts/sum-151124

http://garage.grumpysperformance.co...train-clearances-and-problems.528/#post-57678

http://garage.grumpysperformance.co...ting-up-the-valve-train.181/page-2#post-54091

http://garage.grumpysperformance.com/index.php?threads/what-springs.11352/#post-51960

http://garage.grumpysperformance.co...-loads-and-installed-height.10709/#post-46627

http://garage.grumpysperformance.com/index.php?threads/removing-valve-seals.4283/#post-44287


http://garage.grumpysperformance.com/index.php?threads/the-new-215cc-vortec-heads.266/#post-35948

http://garage.grumpysperformance.co...-vortec-heads-and-other-heads.401/#post-34996

http://garage.grumpysperformance.com/index.php?threads/vortec-info.529/#post-27299

http://garage.grumpysperformance.co...o-the-large-port-vortec-heads.1040/#post-1943

http://garage.grumpysperformance.com/index.php?threads/vortec-related-info.731/#post-1028
 
Last edited by a moderator:
1935garwoodspeedster said:
boat weight should be around 2000 lbs (dry) reproduction 1935 Garwood Speedster.
Click to expand...

How about a picture of this beauty?

I have no idea what a 1935 Garwood Speedster looks like!

 

this is my progress so far, i hope to get the bottom on it this year which would mean flipping it over and starting on the inside (engine and plumbing) early in 2016. So basicaly i need to start planning and saving for the motor, trans, and other stuff.

http://www.vintageraceboatshop.com/Obsession.htm
go to link above and scroll down to the second large picture for a good look at what mine should look like when i finish. I even plan to use the side exit exhuast. the link above is a 21' and they are using a 454 stroker, mine will be 16' and a 383 if i can make all the numbers and budget agree!
 
Grumpy,

thanks for the info.

one question, I see that the cam setup you linked is a "Hydraulic Flat Tappet". I have heard that flat tappet motors dont last as long as the hydraulic rollers do, is this true?
if so would upgrading the motor to such a hydralic roller setup prove to be cost worthy with respect to engine life and the headache that it is to pull a motor this size out of a boat this small...lol

Ill be running a 1/2 raw water system IE (raw water pumped from freshwater lake threw a heat exchanger, then threw the engine headers, and finally exhuasted threw the wet exhaust system back into the lake. nothing but antifreeze running threw the engine! as you can see, although i am budget minded with my build i also dont want to rebuild the motor every couple of years if i can help it, know what i mean?
 
wow those pictures of the obsession boat look beautiful. what a cool project!
 
1935garwoodspeedster said:
Grumpy,

thanks for the info.

one question, I see that the cam setup you linked is a "Hydraulic Flat Tappet". I have heard that flat tappet motors dont last as long as the hydraulic rollers do, is this true?
if so would upgrading the motor to such a hydralic roller setup prove to be cost worthy with respect to engine life and the headache that it is to pull a motor this size out of a boat this small...lol

Ill be running a 1/2 raw water system IE (raw water pumped from freshwater lake threw a heat exchanger, then threw the engine headers, and finally exhuasted threw the wet exhaust system back into the lake. nothing but antifreeze running threw the engine! as you can see, although i am budget minded with my build i also dont want to rebuild the motor every couple of years if i can help it, know what i mean?
Click to expand...
a hydraulic roller cam , with duration , LSA and lift similar too or like this
http://www.crower.com/camshafts/chevy-2 ... 16180.html
will produce better power and last longer but you stressed "BUDGET BUILD" so I went the least expensive route
READ THRU THIS THREAD
viewtopic.php?f=52&t=82
 

Now that is a labor of love!!! Has to be with the precision and the amount of
time required to build that boat by hand!!! Wow!

The cam the Grumpy spec'd is a step nose or also call a Late Model, hence the
LM in the part number. The block you have will determine what nose you need
on the cam. Also if it is a Late Model nose, there are two different thrust plates
IIRC.... just beware when you go to buy.

The two bolt holes point out by the RED arrows is for the thrust plate in the
2nd photo.




You may have a block that has no thrust plate, therefore it will use the cam
button. Sorry don't have a pic of the cam button.
 

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I have allot respect for you I worked one winter on a scooner replacing some ribs and replacing the bottom. Allot of work and crazy what goes into it with cutting changing angles. Even what goes into caulking in between the seems with hemp.
 
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